The Serengeti is renowned for being one of the few relatively intact large ecosystems remaining in the world. Sure, it isn’t without its problems, nowhere, not even protected areas (PA’s), are exempt from the onslaught of effects from humans either directly on the ground or through climate change but in general the health of the Serengeti is robust.
So why is it in this well balanced, large ecosystem that we don’t ever see African wild dogs (Lycaon pictus) on the Snapshot Serengeti cameras? Of course, African wild dog numbers everywhere are low even within (PA’s) but they are part of the carnivore guild alongside lion, leopard, hyena, cheetah in most of the big PA’s like South Africa’s Kruger National Park and Botswana’s Okavango Delta. So why not the Serengeti National Park (SNP)?
Not so long ago wild dog were present in the SNP in small numbers. In 1970, when studies began, there were an estimated 95 individuals in 12 packs. They were studied sporadically until 1991 when all 12 packs had seemingly died or disappeared. Here in lays the mystery, what killed them?
At the time the rapid disappearance of the wild dogs coincided with a renewed period of research that saw individuals from several packs immobilised and fitted with radio collars. The research community at the time were baffled and a hypothesis was proposed by Roger Burrows that implemented researchers handling of the dogs as being causal to their decline, the theory being that the stress imparted to the animals made them susceptible to rabies which eventually killed them. It is a controversial hypothesis and has had the research community at each other’s throats for the last 25 years. Some argue that invasive handling of study animals is un-ethical and can lead to tragic outcomes (as hypothesised by Burrows for the African wild dog) others argue that collaring and taking blood samples from study animals is vital to understanding processes which effect conservation management.
A recent paper by Jackson et al, “No evidence of handling‐induced mortality in Serengeti’s African wild dog population” an open access paper published in Ecology and Evolution, revisits the question and aims to shed new light on the argument with research.
I am not trying to weigh in on the argument, my expertise is inadequate for that but I thought it was an interesting take on the question of wild dog in the Serengeti and it used data generated by Snapshot Serengeti, all be it in a small way, to help with its argument.
Surrounding the eastern side of the SNP are two PA’s, the Ngorongoro Conservation Area (NCA, a multi use area occupied by a large population of Maasai pastoralists) and Loliondo Game Controlled Area (LGCA, a multi use area with some settlements, hunting and tourist concessions.) One would argue that these areas are not as pristine as SNP itself with a good dose of human impact but the wild dogs have been studied here since 2005 and as of 2017 there was an estimated population of 120 individuals in 10 packs.
Collaring has shown that the wild dogs do venture back to the Serengeti plains from time to time (proving there is no physical barrier to dispersal) but that they do not settle there, choosing instead to stay in an environment where one would imagine it was harder to survive on the periphery of human habitation. Our own Snapshot Serengeti work comes in to play here to prove that even with an extensive network of cameras that have been in operation for several years no wild dog has been recorded in SNP.
So what do Jackson et al imagine could be the route cause if not the direct handling leading to stress related rabies outbreaks hypothesis.
The team have studied wild dogs for over a decade in areas adjacent to SNP that arguably have an equal or higher rabies risks (think of the domestic dogs associated with people) to the SNP. They have used the same invasive methods of study as the SNP researchers including using intervention to fit collars, take blood and in one incidence an attempt at relocation back to SNP. They believe that they have the perfect scenario in which to test the hypothesis.
They found, in contrast to the earlier study which saw the entire population disappear, that 12 month survival rate in handled wild dogs was 87.6% and in a group of 67 wild dogs captured and translocated back to SNP, held for almost a year in translocation enclosures, a long term stress situation, 95.5% survived over 12 months. Incidentally, most of the relocated dogs did not stay in the SNP, returning to the adjoining PA’s. One pack did remain but not in the former study area of grassland plains but rather in a rugged area just outside the original study area.
The team argues that the wild dogs in both NCA and LGCA have been subject to handling just as much as the original study yet have shown a population increase, secondly, there has been no repopulation of the original study area either naturally through dispersal nor through attempted reintroduction something that arguably should have happened if the only reason for the die off was human induced.
Instead they believe that the demise of the wild dog coincided with a rise in lion and hyena numbers on the plains of the Serengeti. Wild dog are killed by these predators but perhaps more importantly they also have their hard earned prey stolen from them by larger predators. Their theory is that the competition from increasing lion and hyena numbers as well as out breaks of rabies and canine distemper saw the death of some packs and the dispersal into the adjoining PA’s of the rest. Compared with the endless grassy plains of the Serengeti, the NCA and LGCA are much more varied terrain with a mixture of hilly, rocky areas as well as open woodland and open grassland. This kind of mosaic gives wild dogs a much better chance of avoiding larger more dominant predators and so their chance of survival is greater.
So could this be why we see no wild dog in our camera traps. Whatever the reason it highlights that even with what we imagine as well protected areas the space we have left for wildlife is minimal and to protect a wide range of biodiversity we should be doing more to protect a wide range of ecosystems and habitats.
If you want to read the Jackson paper you can find it here: https://onlinelibrary.wiley.com/doi/abs/10.1002/ece3.4798
There are links within the paper to the original Burrows work so you can get a feel for both sides of the story.
I recently met with Meritho, who has to have one of the best jobs in the world; he is paid to watch lions.
Yes it does sound like the dream job, following lions all day, observing their behaviour and trying to identify them but Meritho’s job is not quite the dream it would seem. For various reasons the long running Serengeti Lion Project was put on hold for three years which meant that all the diligently followed lion prides known intimately by researchers have done a lot of growing up, giving birth and dying. Not surprisingly it’s hard to work out who’s who and who belongs to whom.
Meritho has inherited the arduous task of re-establishing the family connections and splits within the Serengeti’s lion prides. Armed with some old scribbled maps and a stack of cards with drawings of lion whisker spots he has to compare each lion he sees with these cards to help him workout just who is still out there in the Serengeti lion society. Of course the camera trap images help a little but only if they capture the perfect close up, in focus image of the lions muzzle showing the spot pattern. In reality its all down to traipsing around the Serengeti looking out for lions and comparing each and every one with the hundreds of hand drawn cards.
I asked Meritho how he tackles this mammoth task. Making a plan is key, he says, with most of the tracking collars non functional you have to think hard where the lions might be and just drive around looking for them.
Ok you can narrow it down a bit as Meritho does by getting up by 5 am, making sure your vehicle is puncture free and stocked with fuel and water and then heading out to try and catch the big cats as they finish up for the night. At this early hour they are often looking for a good spot to spend the day or joining back up with young cubs that have been left somewhere safe whilst mothers where out hunting. All this movement increases his chances of running into lions.
Most of the time Meritho is far from base so eats lunch in the car only returning home around 5:30 as it starts to get dark. Its long hours and most of the time you are either sitting waiting or driving, briefly interspersed with spells actually watching the lions. In return they themselves are often infuriatingly sleepy and won’t lift their heads for you to get good pictures of their whiskers meaning even when you do find lions you cannot always see who they are.
So far he has managed to identify around 150 individual lions and is monitoring around 18 prides. Monitoring lions gives him a sense of pleasure that he is out there doing a scientific job he never dreamt, as a Tanzanian, he would get the chance to do. He says ‘ when I look at where I come from and where I am going as a researcher it brings a lot of value to my life, knowing what research means is one thing but doing research makes me feel like I am contributing something to the world and my home environment’. He is gaining knowledge and experience daily and hopes to continue doing great things within conservation, an inspiration to aspiring local scientists.
It’s great to know that Meritho is out there following the lions again and that the Snapshot Serengeti cameras are still going to be clicking away for sometime to come.
People all around the world know about the great wildebeest migration through the Mara/Serengeti ecosystem. Those of you who classify on Snapshot Serengeti are more than familiar with the thousands of wildebeest and zebra images. A few of you will have been lucky enough to witness the spectacle.
For myself working here in the greater Serengeti ecosystem I have been eagerly awaiting the event since early November and boy, I have not been disappointed.
Having spent most of my time in Southern Africa I haven’t experienced this kind of mass migration before, sure I have seen large herds of buffalo in Kruger National Park and seen the elephant migration from Botswana into Namibia through Khaudom National Park but this here in the Serengeti is something else.
Up until recently the area I work in has been a dust bowl with a few blades of grass and bare branched thorn trees. It didn’t look like it could support much and the lions were becoming thin. Only the little dik dik looked healthy. The area is also home to Maasai herders and so scrawny cows, sheep and goats filled the landscape, conflict between lions and humans was running high.
Then the rains started. Slowly at first, not the dramatic down pours you see in Nature documentaries but teasing splatters that have you willing for more. By mid-December though enough had fallen to tip the balance and the vegetation began to grow.
Shortly after the rumours began, so and so saw a large group of wildebeest to the north, then so and so was camping and heard the distant gnu-ing of wildebeest on the move. Then out of nowhere they were here. Everywhere you look there are hundreds, in fact if the bush was less dense you would soon realise there are thousands. Zebras are here too but not quite so many. Meanwhile the Maasai herders with cows have vacated the area. They avoid the wildebeest who can pass on disease that is deadly to their cows.
With the herds finally here, the lions can relax. They have gone from skin and bones to full and fat seemingly overnight. I am following one particular pride, two of its females have given birth in the last two weeks, absolutely perfect timing (of course this was down to luck rather than judgement as lion don’t have set breeding seasons). I haven’t seen the cubs yet as they are tucked very safely away in some extremely prickly dense bush which is a good thing because the place is teaming with milling wildebeest, zebra and elephant. The mums don’t have to go far for dinner, its more like a home delivery at the moment and the satellite tracking shows this well, they haven’t moved more than about 1.5km from the denning spot! These cubs have a good chance at life.
After a long day of monitoring lions, I found a quite camping spot in an area of more open bush. I took a moment to lay on the ground and close my eyes for a 10 minute nap before dragging myself up again to make tea and set up camp. As I got up, I looked out to a crowd of wildebeest about 40 meters away gently gnu-ing and all looking at me. They seemed so confused that I was there. After a short standoff they turned 900 and continued on their way towards goodness knows where.
That’s the strange thing, when you watch nature documentaries the migration looks so purposeful but when you are in the middle of it, particularly when you are not on the open plains but in thicker bush its harder to tell. Its more of a swirling pattern than a straight A to B and the herds just keep moving round and round the area looking for the freshest new grass. So sometimes you see 100’s moving south only to see another group heading North.
Wherever they are going it is hard to describe how it makes you feel to see such numbers of wild animals. For me it is hope and relief that at least somewhere in this world wildlife seems to be doing ok. For a moment you can lose yourself and imagine what this planet used to look like when things where in balance.
The wonder of nature.
Data collection is the back bone of field research work and can sound glamorous and exciting to those who are office bound but I will let you into a little secret, it can be exhausting and frustrating and unrewarding too.
Firstly, you have to remember that researchers often work in remote places and whilst this is amazing it does lead to some logistical nightmares. Take for instance my recent experience. My task was to visit 18 Ilchokuti or lion guardians from KopeLion to collect the data they had recorded during the previous month. Now they are spread out over 1300k2, in itself quite a distance but when you factor in the rough at best, non-existent at worst roads you begin to have an idea of the task. I would be lucky if it didn’t rain, that would only add to the woes. Another thing to remember is that, barring a few lucky people working for high profile organisations, most researchers have to nurse their aged vehicles along, fixing things as you go. This trip wasn’t too bad as we seemed to only suffer from door catches failing so nothing a bit of string or a Leatherman wouldn’t fix. The budgets just never seem to run to decent cars.
Just as I was about to feel smug about the lack of rain hampering our journey it dawned on me that dry conditions held their bad points too. Dust! The fine dust covering some of the landscape here is deadly. It penetrates everything and with a three-day trip planned with no opportunity for a shower, boy does it get tiring. Forget enjoying the scenery as you drive, you mostly feel as if you are in a cloud only with a yellow tinge that makes it hard to breath in place of the fluffy white.
Anyway, I can’t really complain it was a wonderful three days and meeting up with a couple of our guys in the middle of nowhere under a great baobab tree acting as our office for an hour or so was something to make you smile.
My colleague, Meritho Katei, over in the Serengeti has an even harder job under similar conditions. I was simply rendezvousing with other people, collecting and issuing data sheets and downloading GPS data. Meritho is trying to pick up on the lion monitoring for the Serengeti Lion project that has been on hold for a while.
His task is to reconnect with the prides of lions previously being followed and studied and to catch up on the family histories. New members need to be identified, files made on them and changes in pride composition noted. He is working with the Snapshot Serengeti camera trap data to see where the prides are hanging out but of course we aren’t quite up to date with the classifying so that’s not the greatest help. Instead he is relying on a lot of kilometres driving, following up on tourist sightings and tracking data and a good set of eyes to track down the prides and observe them.
So as I washed the dust out of my hair, luxuriating in a hot shower after my three day successful, mission accomplished trip, I had to reflect that poor Meritho was in for many months of hard slog catching up with those lions and with the rains coming things are about to get even harder. Good luck Meritho!
I have been a little quiet recently and for that I must apologise but my excuse is good. I have been relocating to Tanzania where I am going to be based for the next three months working with Kopelion in the Ngorongoro Conservation Area. One of Snapshot Serengeti’s partners kopelion (Korongoro People’s Lion Initiative) is a conservation organisation and research project that focuses on human-lion coexistence in the multi use landscape of Ngorongoro. I have written about the project in these blogs if you want to read more https://blog.snapshotserengeti.org/2017/02/23/meet-the-people-2/
After a two week intensive language course in nearby Moshi I have finally made it to base camp on the crater rim. The office is perched at 2300m looking down on the Crater Lake and has one of the best office views I have ever had which makes up for being stuck indoors when you would rather be in the field.
It’s not all office based thank goodness and I have already had the pleasure of three days out in the Ndutu area learning about the work the project does. Although there has been some rain it is still in the grip of the dry season here and the scenery for the most part is a dry and dusty yellow. The lions are hungrily awaiting the rains that will bring a welcome flush of green that will draw the wildebeest in vast numbers and thus plenty of prey.
Saturday was spent following up on reports of lion spoor (tracks) found near to an area that Maasai bring their cattle to drink. We turned up early morning to start tracking the spoor to see if we could figure out if the lion where still in the area; if this turns out to be the case a lion guardian or Ilchokuti will stay put in the vicinity to warn herders about the lion presence and hopefully avoid an encounter.
It was obvious that several lion had been in the area, you could see depressions in the sand where they had lay down for a bit of a nap. The tracks lead alongside a small water drainage channel and the lions had wandered down to drink in a few spots. Further along the water channel the tracks of individual lions suddenly converged on one access path down to the water. Clearly something had excited their interest. After a careful look around we descended the same route to investigate. Lying in the mud at the edge of the water we found the body of a young spotted hyena, teeth marks around its throat and the surrounding tracks told the story. Most likely the youngster was drinking when the lions ambushed it, its small size meant it didn’t stand a chance and lions probably quickly dispatched it.
Despite the fact that the lions in the area are somewhat lean at the moment they made no attempt to eat the hyena. This is normal behaviour for lions; they will not tolerate other predators in their territory and will kill them if the chance arises. There was a lack of other hyena spoor in the area so this youngster was probably on its own, why we cannot say but it became an easy target for the lions.
It is a great privilege to walk into an area that has such a story written out for you in the sand and mud. In this instant the presence of a body left little to interpret but the trackers here are capable of reading far less obvious stories and it is this skill that is helping to mitigate lion-human conflict by acting as an early warning system to the people who live side by side with lions.
Our camera-trapping efforts afford us an unparalleled view into the lives of the Serengeti ecosystems animals but the work of conservation has many aspects and I hope to bring you a good view of what is going on here over the next few months.
Photo Credit: Edward Lopatto
These incredible images of a major lion turf war have been taken by the team in the Serengeti and come with the fantastic announcement that the long running Serengeti Lion Project is back up and running.
Although the camera-trap aspect of the project has continued without pause, the main work of the Serengeti Lion project has been on hiatus for the past few years. Now, it is finally being restored and the priority is to sort out who’s who in all the study area prides. Comparing existing id’s and adding new ones is going to take some time.
Looks like these boys are trying to shake up the genes even more. Two coalitions both looking strong have clashed over ownership of prime real estate. The team report that all the males involved looked strong and healthy so this is probably not the definitive battle.
We will have more news for you soon on how the work is going as well as reports from the field, so stay tuned. Meanwhile enjoy these stunning images.
Of all the large birds out there on the Serengeti plains the vultures are probably the most recognisable, with their long barely feathered necks and large hooked beaks, you can’t miss them. For a lot of people they are ugly birds and their behaviour makes people shudder, all that frantic plunging of necks inside messy carcasses. Some cultures revere the vulture, instilling magical attributes to them whilst others vilify them.
But the truth is they are just birds with their own unique ecological niche, one that is absolutely essential to the health of the whole ecosystem.
Lets break it down. That neck, well the fact that the whole head and neck is either bare or only lightly feathered is a marvellous adaptation to keeping clean. Yep, not something people generally associate with vultures but they are in fact pretty clean birds. That beak, well it may look like it could kill quite efficiently but it is actually designed to grip hard and rip. Believe me I have been around rescued vultures and felt the effect, there is a lot of power there. A vulture will use its sizable feet to hold a tricky bit of carcase down when trying to tear off a chunk but the real power comes from the strong neck muscles and the powerful beak.
If you look closely at the different species of vulture you will notice that not only is there a difference in size of individual species but in the beak size. There is a hierarchy in vulture etiquette at a fresh carcase. If the dead animal is large and has a tough hide, say a buffalo, the larger species such as lappet-faced will be needed to ‘break in’. Their huge beaks and added bulk allow them to head straight for the good bits where lesser vultures would have to start with the natural openings such as the eyes, mouth and anus. Once the large vultures have broken in, the rabble takes over and fights it out for the good meat, the white-backed and Ruppell’s. Around the peripheries the hooded vultures will be waiting for the chance to snatch up bits of anatomy that are sent flying by over- zealous cousins or to dart in when the carcase looks almost clean to pick off the last bits of flesh in hard to reach places. It is not uncommon to see this species right inside the empty carcase and its slim lined beak is great at cleaning up.
Vultures search for food from the wing. Research has shown that in the Serengeti it is most often the lappet-faced that arrives first despite the numbers of this species being lower than the others. It seems they are extra vigilant or just have better eyes. The descent of this the largest African vulture draws in the other species who can be clued into the find from over 30kms away. It is quite breath taking to see many vultures on rapid descent with wings held inwards, feathers splayed it can also be noisy.
But other than cleaning up unsightly dead things how do vultures help the ecosystem? Like other organisms that consume dead animal matter vultures are immune to a lot of deadly diseases. Their stomachs are filled with very acidic digestive juices which can destroy diseases such as anthrax, cholera and rabies. Most scavengers would not be immune to these types of disease and what’s more, diseases such as anthrax can lay dormant for decades posing an ongoing risk. Of course vultures alone can’t keep the Serengeti disease free but with their ability to fly over 100km a day they do a darn good job of patrolling the plains and keeping them clean.
But outside of protected areas vultures are in decline. In places like South Africa there has always been a value placed on vultures with Sangoma or witchdoctors prescribing vulture heads for people needing to see into the future to answer big life questions. Of course this has modernised, now people purchase vulture heads to see the winning lottery numbers. Vultures are also targeted by poaching gangs who, in an effort not to have their poaching camps discovered, place poison bait to attract and kill the vultures. India, several years ago nearly lost ALL its Gyps vultures. 95% where thought to have died and the main cause discovered to be adverse effects from a drug called diclofenac that was widely given to domestic stock. The drug has since been banned in India but its use as a veterinary drug in Africa is rising causing major concern amongst conservationists. Loss of habitat is also an issue.
We are lucky that the Serengeti is an ecosystem functioning normally with all its facets. You may be lucky to spot, lappet-faced, white-headed, white-backed, Ruppell’s griffon, hooded and Egyptian vultures in our camera trap images. It is quite remarkable to find this type of balance these days and we thank the vultures for their ongoing services.
I am sitting at home in France in a sweltering 40oc listening to golden orioles calling from the tall riverine trees. I could definitely be in Africa, though if I was I would probably be somewhat reluctant to jump in the river to cool off, something I am about to do, what with all the hippo and crocs that the Serengeti is so famous for.
It has got me thinking though about all our shared birds between Africa and Europe. Hearing the orioles today has made me realise that they will be setting off very soon, in the next couple of weeks probably, for their return trip to their wintering grounds in Africa.
Now the Serengeti is justly known for its rather famous herbivore migration but to me it is utterly fascinating that birds, particularly the tiny ones are also taking part in seasonal movements that cover 1000’s of kilometres.
It’s a dangerous journey, they risk predation, starvation and severe weather and if that’s not enough they have to pass over several places where humans think blasting as many of them out of the sky as possible is sport. For the birds migrating from Europe to Africa they have to fly over open sea and a lot have to negotiate the Sahara Desert, an area around the size of the United States. It is estimated that 500 million birds have to cross this unforgiving wilderness and some do it in a long nonstop flight. Just imagine how exhausted they are the when they reach the safety of the green belts that fringe it. My husband used to work in the Sahara and can attest to finding dozens of swallows just lying panting on the ground, being able to pick them up and give them water before launching them onwards.
So why do they do it, well much the same reason as wildebeest and zebra do, resources. Birds have the very special ability to travel very efficiently, it has been said that a small bird can fly the same distance in hours that an elephant would cover in three days. With this ability birds are able to switch geographical areas in order to take advantage of seasonal food supplies and so they enjoy the best of both worlds in terms of food abundance despite the risk involved with moving the great distance between the two. Risk versus reward.
Unlike the Serengeti herbivore migration birds have many different strategies when it comes to undertaking their colossal movements often depending on the species unique design. Many small passerines will migrate in small groups, travelling at night and will try for the shortest, most direct route. A kind of fast and furious approach that relies on having fed up well and being able to feed quickly at the few places they do stop to refuel. Other birds, particularly waders will take a more leisurely approach flying down waterways and coasts, stopping for days or weeks at a time to feed up before moving on. Many raptors and storks cross the Mediterranean Sea over Gibraltar and Tarifa in Spain. It is roughly a 14 kilometre crossing. It is an amazing spectacle to see. Thousands of birds can be seen soaring around in the late morning over land waiting for the thermals to build up which they will use to ride across the sea to Africa. It’s kind of like surfing only on hot air.
Once they get to Africa of course they have a huge choice of where to go and they spread out accordingly, many making it all the way to South Africa. In fact we still don’t know where a lot of them go, something that is vital to understanding the threats facing them today.
So who are the feathered migrants that we may see in the Serengeti? Well across Tanzania there are thought to be around 160 species of Palaearctic/African migrants. The Palaearctic is a large region covering Europe, Russia, North Africa, Arabia and parts of Asia so that’s a lot of movement.
Some of Europe’s smallest birds can be found in the Serengeti amongst them willow warblers, wood warblers and blackcaps. Spotted flycatchers and several shrikes can be easily seen. The common cuckoo is trickier as it is, like many migrants, silent outside of its breeding ground. European bee-eaters and rollers meet up with their African cousins as do barn swallows and common house martins.
Even raptors make it to the famous park; lesser spotted, steppe and imperial eagles all breed in the Palaearctic. Eurasian marsh harrier, black kite and common buzzard all enjoy the warm African conditions before heading back north to breed.
For Snapshot Serengeti followers the most commonly seen migrants on our camera-traps are probably storks, white storks and black storks all take the long journey north for breeding. More surprisingly given it is not noted for its water even European ducks have been spotted in the Serengeti, wigeon, Eurasian teal and garganey amongst them.
This is not an exhaustive list but gives you an idea of the level in which the two continents are connected through their shared avian fauna and reminds us of what a truly global planet we live on.
Symbiotic relationships are common in the Serengeti. They fall into two main types, mutualism, whereby both partners benefit from one another and commensalism, whereby one partner benefits from the actions of the other but the other partner is largely unaffected or unharmed. I wrote recently of oxpeckers and large herbivores, large herbivores provide food in the form of ticks for the oxpeckers and oxpeckers provide a cleaning service for the large herbivores, a good example of mutualism. Birds such as cattle egrets that follow buffalo around to catch the invertebrates the buffalo disturb as they graze is an example of commensalism. Of course it is not just animals that have symbiotic relationships; my blog last week on termites and mushrooms was another example of mutualism.
So what about zebras and wildebeests? We see them all the time on Snapshot Serengeti in mixed herds, grazing peaceably with one another. Is this just coincidence or is this a form of symbiosis?
It is actually hard to say and of course that is why labelling things, especially behaviour is often tricky.
Zebra and wildebeest are both grazers meaning they mostly eat grasses but that doesn’t mean they share the same diet. They preferentially eat different parts of the plants that they consume. Zebras are quite content chewing longer tougher grasses where as wildebeest prefer shorter, more tender shoots. This partition of resources means they can quite happily graze side by side with out exerting pressure on each other.
Another good reason to team up is the extra safety that numbers provide. Not only do more ears and eyes provide better early warning systems but the odds of the individual being targeted by a predator are reduced when there are greater numbers to choose from. Apparently zebra have better eyesight but wildebeest have better hearing so the two complement each other.
There could be another reason. Our very own Meredith Palmer just published a paper about interspecies reaction to each other’s alarm calls, you can read it here: https://www.sciencedirect.com/science/article/pii/S0003347217304207
She found that zebra, wildebeest and impala recognise each other’s alarm calls but that they did not always respond in the same manner. When zebra sounded the alarm all three herbivores reacted strongly but when impala gave the alarm zebra where likely to ignore it, or assess the relative danger themselves. It seems that this varied response is down to predator size. Impala are prey to a wide range of smaller predators that would not be able to handle a mammal the size of a zebra, so when impala give the call it doesn’t always signal danger for the zebra. However when a zebra, the largest of the three herbivores sounds the alarm, whatever it has seen will probably be able to take down the wildebeest or the impala too so it’s prudent that all three scarper.
It is an interesting reaction and maybe wildebeest hang out with zebra because they are more trustworthy alarmists. I am not sure that the companionship of zebra and wildebeest can be classed as symbiotic I think it is more of an interaction due to a shared habitat but it seems that on some level they can benefit each other.
Snapshot Serengeti has around 225 camera-traps laid out in a grid in the heart of the Serengeti National Park. They have been there for around 7 years and make up one of the longest running camera-trap monitoring projects in the world. Snapshot was launched on the Zooniverse portal in December 2012 and has inspired many more similar camera-trap projects from around the world. So Happy 5th Birthday to us, may there be many more to come.
There is no doubt that camera-trapping has gripped the hearts and imagination of both scientists and the public. Eight years ago when I first used camera-traps I had to explain them very carefully to friends and family as they had never encountered them, these days references to camera-traps appear in popular press articles and wildlife documentaries and most people have a basic idea of their use in conservation.
It was K. Ullas Karanth, an Indian wildlife zoologist, who is credited with pioneering the use of camera-traps as scientific tools in his study of tigers in the 1990’s. In the last two decades the technique has advanced at a hugely fast pace and has revolutionised the study of elusive and seemingly well known species alike. It is a scientists dream to observe animals without being present yourself to influence their behaviour.
But looking at the history of the discipline I can across many references to much earlier work using camera-traps. Back in 1927 National Geographic published an article by Frank M Chapman titled delightfully “Who Treads Our Trails”. The piece opens with this amazing paragraph
“If there be any sport in which the joys of anticipation are more prolonged, the pleasures of realisation more enduring, than that of camera trapping in the Tropics I have yet to find it!”
This guy would have loved Snapshot Serengeti. This is most likely the very first scientific paper to report on using camera-traps all be it very different cameras. His rig involved a tripwire the animal steps on rigged up to the camera shutter and bowls of magnesium that will explode and create the flash needed to illuminate the animal at night time. It seems incredible now that this would be allowed considering today’s ethically minded ethos but the author himself points out that the alternatives to studying animals could include using dogs or trappers to catch an animal or even poison bait. He decides he wants a census of the living not a record of the dead and so the idea of camera-traps for scientific study are born. He drew heavily from the work of George Shiras who published the first pictures taken by remote camera back in 1906 (also in National Geographic). George Shiras took the pictures for the pictures sake only later becoming involved with conservation but Frank Chapman was a true scientist.
Obviously the technology has changed a lot and the loud noisy explosions that accompanied Franks work have been replaced by covert black IR where even the glow of the infra-red flash is almost invisible. He would marvel at the amount of pictures that can be stored on an average SD card and that camera-traps are being used from the tropics to the snowfields of Antarctica.
You can look for the original article with this reference:
Chapman, F.M., September 1927. “Who Treads Our Trails?“, National Geographic, 52(3), 331-345
Or visit this site to see some of Frank Chapman’s images: http://www.naturespy.org/2014/03/camera-traps-science/