The Snapshot team have written another paper using the Snapshot data we all help to classify. The paper A ‘dynamic’ landscape of fear: prey responses to spatiotemporal variations in predation risk across the lunar cycle can be found at http://onlinelibrary.wiley.com/doi/10.1111/ele.12832/full for those of you interested in reading the original.
Lead by Meredith Palmer the paper explores how four ungulate species, buffalo, gazelle, zebra and wildebeest respond to predation risk during differing stages of the lunar cycle. These four make up the bulk of the African lion’s diet in the Serengeti along with warthog. Of course warthog are strictly diurnal so are not affected by the lunar cycle as they are tucked up nice and snug in a burrow.
For the other four night time can be a stressful time. None of these animals sleep all night, they snatch rest here and there, keep grazing and most importantly of all keep a watchful eye or ear out for possible attack.
It has long been thought that prey species territory is shaped by fear and that animals have safe areas (where they rest, give birth, etc) and risky areas where they instinctively know predators may be lurking. These areas trigger a risk versus reward response as they often contain better forage/water etc.
What Meredith and the team argue is that this landscape of fear is very much dynamic changing not only with seasons and night and day but on a very much finer scale as influenced by light availability through the moon.
Lions find it so much easier to hunt during nights where the moon gives of least light. It gives them a great advantage to stalking close to their prey using the dark as a kind of camouflage. The prey species, on the other hand, are at a distinct disadvantage, they can’t see the stalker and even if they sense its presence they are reluctant to flee as this presents a great risk in itself if they can’t see.
Meredith and her colleagues took the data from Snapshot Serengeti to quantify nocturnal behaviour of the key species using the presence or absence of relaxed behaviour (defined when we classify a species as resting or eating.) They then overlapped this with data collected through Serengeti Lion Project on lion density and hunting success. This data enabled them to work out what areas where high or low risk to the prey species. Using a clever statistical program, R, the data was analysed to see if lunar cycle had any bearing on animal behaviour, in particular, predator avoidance.
They found that moonlight significantly affected the behaviour of all four species but in a variety of ways. As we mentioned before there is often a good reason to venture into the high risk areas and the trade off in increased risk of predation is a really good feed. Buffalo for instance don’t change their use of space so much but were found to form more herds on dark nights. It seems safety in numbers works well for buffalo. Zebra react similarly in their herding activity but are much more erratic when it comes to space use, moving around a lot more randomly keeping potential predators on their toes.
Each species showed an aversion to using high risk areas at night but, particularly wildebeest and zebra, were found to increase their use of these areas when the moons luminosity was higher and safety increased. It was noted that high risk areas where avoided more frequently in the wet season than the dry. The thought being that there is increased hours of moonlight during the dry season that the animals take advantage of. Perhaps too the drive to find enough good food is a factor.
This paper serves to remind us that although what we do at Snapshot Serengeti is fun it is more than just a way for us classifiers to pass the time. It really has a very significant role in science and that role is ever increasing.
The Serengeti plains hold a wealth of wildlife familiar to us all. As long as our camera trap images are clear most people have no problem identifying wildebeest, zebra, giraffe and impala. It is some of the smaller antelope that prove a bit of a problem. The smallest of the Serengeti’s antelope, the dikdik is not so well known but what it lacks in size it makes up for in a fascinating life history.
So what makes this diminutive antelope so special and how does it survive living in the lion’s den, so to speak.
It is the antithesis of the wildebeest. Instead of running as a herd of thousands the dikdik live fairly sedentary lives, instead of a constant male battle for mating rights to a harem of females the dikdik forms pair bonds that last for life. Essentially it opts for a quite life under the radar. Living in bushy scrub and kopjes gives it plenty of places to stay hidden and its ability to reach up to 42km/hour enable it to escape even the swiftest of predators. Though of course dikdik do end up on the menu sometimes.
Dik dik are territorial and use dung, urine and scent to mark the boundaries. The scent comes from preorbital glands on the face which is rubbed on sticks. All members of the family will contribute to these markers but it is the male that does most of the work. The strange twist is that males are subordinate to females in the pair bond so really the male is marking and defending his mate’s territory for her. I guess it pays to keep your missus’ happy when you pair for life.
Obviously whilst holding a territory you will have neighbours and that is certainly the case for dikdik pairs but it seems that the peace is kept by making sure you only add more dung/urine/scent to your side of the heap. Dikdik must have the most defined territory of any antelope in the Serengeti. If there is a border dispute it can lead to mass pooping; as many as 10 dung piles per 100 meters which is three times as many as a normal border.
Traditionally there were thought to be 4 species of dikdik mostly restricted to East Africa with one, Damara dikdik, found in Namibia. New work suggests that the four subspecies of Kirk’s dikdik are actually full species making Cavandish’s dikdik (madoqua cavandishi) the species we are familiar with from the Serengeti. It’s hard to keep up with systematics.
One of the most amazing adaptations in dikdik’s is their central cooling system which allows them to live in arid, hot conditions. To cool down they increase their breathing rate from 1 to 8 breaths per minute. This passes over numerous blood vessels in the flexible proboscis (that oversized long snout that makes dikdik look so odd) cooling the blood. From here the cooled blood passes back to the heart through the cavernous sinus. Due to the large surface area in the sinus as hot blood is pumped to the brain a form of heat exchange takes place allowing cool blood to be pumped to the brain ensuring that brain function is not impaired by hot conditions even if body temperature is elevated. This is a trait that dikdik share with other dessert adapted animals such as oryx and camels.
So small it may be but the dikdik is not to be dismissed without some appreciation for its ability to survive in pretty harsh conditions.
Whilst we all love to see lion, cheetah and leopard, the big cats of the Serengeti, their smaller cousins are fairly elusive. I am referring to caracal, serval and wildcat. These three small cats manage to slink around between the large carnivore guild keeping themselves to themselves. Lion cheetah and leopard not to mention hyena will all kill small cats. Despite their diminutive size their larger cousins still see them as competition and threat. All three are solitary cats and to survive in this very competitive world they each have their own niche.
The largest of the small cats, females weigh in at around 10kg and males up to 19kg. They are found across Africa, Arabia and parts of India preferring drier habitats such as savannahs, steppes and dry woodland. The caracal is a magnificent hunter. It is extremely powerful for its size and is able to take down prey as large as small antelope like duiker and bushbuck. The bulk of their diet is made up of hares, rodents, hyraxes and antelope but they are renowned for their ability to leap into the air to catch flushed birds. Their back legs are longer than their front legs and are endowed with powerful muscles that enable them to burst upwards and snag flying birds.
This cat is uniformly coloured the bulk of its body ranging from a tawny grey to a brick red with some spotting restricted to its pale cream underbelly and chin. Its most distinguishing feature is its black tufted ears and black facial markings as well as a short stubby tail that put one in mind of a lynx. It is in fact not related to the lynx family at all.
Probably the most easily recognised of the three and the most commonly encountered of the cats on Snapshot Serengeti. These exquisite little animals are restricted to the African continent south of the Sahara across savannahs, marshes and forest edges particularly near water courses where tall grassy plants grow.
The serval weighs between 6 and 13 kg with males being larger than females. Proportionate to its size it has the longest legs of any cat species and along with its elongated neck and large pointy ears makes this cat unmistakeable. Its tawny coat is spotted black; these spots may run into bars on its neck, shoulders or legs. Melanistic (all black) morphs are known and we have been lucky enough to capture this rarer variation on Snapshot camera-traps.
Food wise these cats are small mammal specialists stalking prey through long grass locating their prey by sound and then using their long legs to leap into the air and strike prey in a fox like manner. They have very flexible toes and will hook fish and amphibians out of water as well as mammals from burrows. The bulk of their diet consists of small rodents under 200g but they will take reptiles, amphibians, birds and small antelope.
These cats are smaller than the other two, heavily resembling a domestic cat it is found throughout Africa, Asia and Europe. They weigh between 2 and 6kg and like the caracal and serval males are heavier than females. Apart from size the appearance of the sexes in all three cats is very similar and show little dimorphism.
Its coat is highly variable in colour and pattern ranging from grey brown to red. Dark spotting tends to appear towards the rump, down the tail and on the legs which often bleed into each other appearing more like dark stripes.
It is perhaps more of a generalist than the other two small cats and takes a wide variety of small prey with rodents making up the bulk of its diet. Birds are less frequently taken but insects have been identified as an important part of the diet. Its method for hunting is more familiar to us than the stalk and pounce of the caracal and serval. It will locate prey by sight or sound and then silently creep towards it by slinking belly to the ground before pouncing at the last minute. We have probably all witnessed a domestic cat stalking like this.
Of course once you are familiar with these three cats it is easy to tell them apart, that is if you are lucky enough to get a good daytime or colour image. Although serval are seen out in the day caracal and wildcat are less frequently active during daylight and all three mostly hunt at night. It can be harder to tell one from the other in a black and white night image but the trick is to concentrate on the shape. Does it have outsized ears, long legs and obvious spots (serval) or a rounded head on powerful shoulders and ears with tufts (caracal) or does it really remind you of the proportions of a domestic cat (wildcat). Like always make your best guess and perhaps post on the descussions page for more help.
Some of you will have noticed that our progress bar on season 10 has not been showing any progress. Well it turns out that we have made loads of progress, it’s just the bar that was not getting anywhere.
The good folks at Zooniverse have fixed it for us and you will now see we are about half way through season 10 which is fantastic. There are just under 700 000 images to classify this season so thanks to you, are dedicated team of citizen scientists we have around 350 000 left to go. That’s 350 000 chances of finding that one image you have been waiting for. I have noticed recently lots of you posting on talk that you have classified your first ‘waterbuck’ or ‘serval’. If you haven’t discovered your dream find yet there is still time and yes there is a season 11 in the wings.
Whilst on the subject of talk I wanted to gently remind everyone of a few etiquette points.
#Hashtags, love ‘em or hate ‘em they are part of social media and they are not going away. On Snapshot Serengeti we use them for a specific reason and that is to help others to search for and find certain images.
If you have found a great image that you think others will want to see and you are certain of the species then go ahead and hashtag it, but, if you find an image that you are not sure of then please don’t hashtag it with your guess. You can still put the pictures up in talk for discussion and perhaps someone else will be along who is positive about the id and can then hashtag it. Basically, please use hashtags thoughtfully.
Which brings me to another point; if you can’t identify an image and you post it up for discussion always give us your best guess. No one will laugh; it’s what makes it fun seeing what other people make of the images when you are really stumped. Many a time I have confidently shared a tricky image almost certain for instance it’s a long sort after rhino only to have someone else’s eyes point out that if I look a bit closer that actually it is a rock! Even our expert modifiers get things wrong occasionally and are reluctant to confidently make a call on certain images. Some of them are just so darn impossible to id. So just give it your best shot, it’s what everyone else does.
The main aim is to enjoy yourself, challenge yourself and use other peoples experience when yours fails you. The Snapshot family of classifiers and moderators is a dedicated and knowledgeable bunch and as I have said before, this project would not exist without you all. Keep up the great work one and all.
World lion day was set up to raise awareness of the conservation issues facing lions today. The African lion, listed by the IUCN as vulnerable, and the Asiatic lion listed as endangered are facing the triumvirate threats of habitat loss, human conflict and poaching.
Most of you who read my blogs will probably be aware of the threats and today there will be some really informative media pieces out there on the web if you are not penned by the world’s leading lion conservation organisations.
I thought instead that I would concentrate on the other side of World Lion Day, which is the celebration of the animal itself.
The first time I saw lion in the flesh was in South Africa’s, Kruger National Park. A car was stopped seemingly watching two tawny eagles perched in a tree. Now being a bird lover I couldn’t pass up this opportunity to get a good close look at these birds so I stopped too. Gazing up admiring the birds I became aware of the occupants of the other car waving at me, trying to get my attention. They were frantically pointing down under the bushes, following their jabbing fingers I found what they wanted me to see, four tawny legs poking out from under the bush, as if she heard me, up came a head, gave my presence a fleeting thought then slumped back down to sleep. My heart ready to burst with joy I grinned back at the car opposite then as I turned my glance back to the sleeping lion I caught a glimpse in my wing mirror that sent my heart racing. Two huge lions filled the mirror walking down the side of the car towards me. For an instant I forgot I was inside and a bolt of primal fear shot through me. But the lion were not interested in me, just the shade of the nice bush.
Lion have long been revered by man. The Eurasian cave lion has been immortalised by Palaeolithic man in cave art such as that found in Frances Lascaux and Chauvet caves. The Chauvet caves are thought to be the oldest rock art in the world dated at over 30 000 years old. Our very own Dr Craig Packer had the privilege to go into the caves to analyse these lion images. Only a handful of people have ever been inside the caves in an effort to preserve them.
Modern lions probably originated in eastern and southern Africa around 120 000 years ago where they then spread across Africa, south -eastern Europe, the Middle East, South Caucasus and into India. Ancient Greek writers suggest they were still present as recently as 100 BC in Greece and the Balkans. Lions survived in parts of Mesopotamia and Syria into the 19th century when the proliferation of guns saw their demise.
Their image, even today, is commonly used in heraldry as a symbol of strength, nobility, bravery or royalty. The ancient Greeks had many myths and stories of lion and their buildings and statues are resplendent with lions. It is easy to see why they are the most commonly used animal in heraldry. Even today in our jaded world lion are loved by many and as the example of Cecil the lion shows can elicit a huge emotional response from people the world over.
Let’s hope that on this World Lion Day that the tide can start to turn on the conservation fight for these glorious animals and we don’t lose that long history we have with the King of Beasts.
This summer in South West France has not been its usual hot balmy self. In fact as I look out the window now the overriding colour is a deep lush green. Normally by July it is turning a straw yellow colour but this year we have had plenty of rain. In contrast, to the south of us, fires have been raging through Portugal, Spain and South Eastern France. Who knows if this is a taste of what’s to come or a one year glitch in the system but one thing is for sure climate change is going to affect life on this planet in both subtle and not so subtle ways.
I wrote about termites last week and their importance in the ecosystem. This week I read a disturbing news article about aardvark, who of course survives on eating termites and ants.
A group of scientists in South Africa were studying aardvarks in the Kalahari. They had inserted biologgers into several aardvarks in order to follow their activity and body temperature. It turned out that the year of their study was an exceptional year of draught and all but one of the study animals along with others in the area died. They unexpectedly recorded a phenomenon not seen before that should be an eye opener to the ways in which future climate could affect not only individual species but whole ecosystems.
The aardvark themselves can withstand high temperatures but the termites on which they rely for food and water cannot. With the information provided by the biologgers the scientific team where able to see that the aardvark were not finding enough termites or ants to keep their energy levels up. Night times can be pretty cold in the Kalahari and the team found that the starving aardvark even swapped their usual night time foraging behaviour to day time in order to conserve body energy. They were even seen sunbathing in a bid to save energy. It seems that none of this adaptive behaviour was enough. There simply was not enough food for their needs and they slowly starved to death. At an average weight of 60 to 80 kg an aardvark is a large animal and needs to eat around 50 000 termites or ants a night.
One or two bad years will always happen but if climate change shifts as it is predicted many areas of Africa will become drier and hotter creating an aridity that most of the native termites and ants cannot tolerate. True, given time, more tolerant species may take over but in the meantime the much loved aardvark may become a creature of the past. But that is not the end of the story. The aardvark is more than just a curiously put together animal, it is the architect of large burrow systems that many other mammals, birds and reptiles are reliant on to escape extremes of hot and cold weather, to bring up their young and escape from predators. Most cannot excavate the hard earth themselves so with the possible demise of aardvark life would get a whole lot tougher for many many more animals.
If you want to read more about the study have a look at this link https://africageographic.com/blog/aardvarks-beating-climate-change/
The Serengeti is one of the best examples of a fully functioning grazing ecosystem. It is home to the world’s largest body of free roaming herbivores. If you have helped classify snapshot Serengeti’s millions of camera-trap images you will know that wildebeest, zebra, topi, hartebeest, and gazelle to name a few are far more common than lion, cheetah and leopard.
Most people are aware of the millions of antelope that, along with the grasses themselves, shape this environment but they are not the only herbivores out there. There is a micro world down at ground level that is often forgotten about but which plays an enormous role in the functioning ecosystem; herbivorous insects such as grasshoppers, beetles ants and termites.
I want to take a look at termites. When most people imagine an African savannah they think of an endless vista of gently swaying grasses interspersed with the odd umbrella shaped tree and termite mounds. Termites are an integral part of the ecosystem here and it is thought that in terms of biomass they exceed the combined weight of the Serengeti’s mammals. They consume dead plant matter above ground (often during the night) then retreat underground where anaerobic bacteria in their stomach gets to work on breaking it down into a useable form, this is very similar to the process in ruminant herbivores.
Why are termites so important to savannah ecosystems? Well they serve multiple functions such as nutrient cycler’s, habitat architects and as food for other animals.
The daily activity of millions of tiny termites who bring dead vegetation into their underground homes helps to circulate nutrients with in the soil layer as well as aerating the soils themselves. If you ever get to look at a termite mound you will see that the grasses on them are often cropped short were as the surrounding area is full of long grass. This is because the grasses growing on the termite mound are particularly nutrient rich, thanks to the termites having created a nutrient hotspot and wildebeest, topi and zebras all know this and preferentially munch this grass.
Termite mounds shape the plains around them giving a relief to the flatness. Other animals such as topi, hartebeest and cheetah will use these small hills to climb onto to get a better view of their surroundings. In this flatness even a few inches of elevation could give an advantage. Many animals use termite mounds to create their own burrows. Hyena, warthog and jackal will use them as dens but the master creator is the aardvark who does most of the excavating. Snakes, lizards and mongoose readily take to old mounds too.
Termites are nutritious critters themselves and almost any omnivorous animal will make a meal of them when the chance is offered. I remember seeing about twenty large raptors walking around on a dirt road in the Kruger Park looking like a flock of chickens gobbling up termites after an eruption.
Then there are the termite specialists, aardwolf can consume around a kilogram of termites in a night. Another predator is the ant, whispering ants will raid termite mounds grabbing worker termites, carrying two or three each at a time back to their own nests.
All in all termites are a hugely important part of the Serengeti ecosystem playing a vital role in so many lives be it nutrient provider, habitat provider or as food themselves. You will probably never classify a termite on snapshot Serengeti but it’s worth remembering just how important they are.
Here on the Snapshot blogs we seem to concentrate on talking about the animals that populate the Serengeti. Of course these are the subjects of our many camera-trap images (oh, apart from those annoying over grown vegetation ones) and they are loved by us all but for once I thought I would talk about the Serengeti itself. Monitoring the animals that live in the Serengeti is a valuable way to assess the health of the landscape but to get a true idea of the state of play the whole ecosystem needs to be looked at. More and more scientists are realising that a holistic approach is needed to truly understand what makes an ecosystem tick and how to preserve it. Studying lion without looking at their connection to wildebeest and grass is like studying maths by looking at the numbers without the plus or minus signs.
So we have all heard of the Serengeti but what do we really know. It surprises me how many friends don’t actually know what country it is in. The Serengeti National park, where our 225 camera-traps are located is in Northern Tanzania bordering Kenya’s Maasai Mara National park. The two together with the Ngorongoro Conservation Area and other private game reserves make up the Greater Serengeti Ecosystem which protects the area of the great migration. It is easy to see where the confusion comes from.
Everyone has heard of the wildebeest migration but did you know that it is one of the largest animal migrations in the world that has not been drastically altered by humans, there are no barriers to impede the movement of the millions of animals that seek fresh grazing and water. The 1000km circular migration route sees around 500 000 zebra, over 1 million wildebeest followed by hundreds of thousands of other ungulates annually. All this is still able to happen thanks to the protected status of the entire ecosystem.
The Serengeti National Park itself is made up of around 1.5 million hectares of savannah. Flat or undulating plains covered in grasses which are nourished with ashy soils derived from nearby volcanoes dominate the landscape. Rocky out crops known as kopjes punctuate the flatness with infrequent river courses and their riverine habitat easing the monotypic view.
So what triggers the massive ungulate migration and all the inherent predator action? At the onset of the dry season grasses begin to dry out and water becomes scarce, ungulates are forced to follow their nose to find food and water. Luckily nature is well designed and there is a well defined gradient across the migratory path that sees differences in place and time for abiotic factors such as rainfall, temperature and soil type. It is these factors that govern what vegetation grows where and how available water is and of course where the millions of hungry herbivores can move to next to satisfy their needs. Once settled across the Mara River they can last out the dry season in the mixed savannah woodlands where food is not so scarce. But the pull of the plains is always there and with the onset of the rains back they go thundering towards the Serengeti once more in a tradition that has possibly been around for over a million years.
The area is the last remaining example of a large mammal dominated ecosystem that existed across much of Africa during the last 1.8 million years. With its relatively intact biodiversity and sheer size it is easy to see why scientists flock to study both the individual species that occur here and functioning of the ecosystem as a whole. Sadly there are not many places like it left on Earth.
Laying in my tent last night listening to nightjars whirring and barn owls screeching I was reminded of the sounds of Africa. As I am away this week with little internet time I thought I would repost this blog I wrote a few years back.
What does silence mean to you? Maybe it’s that moment at the end of the day when the telephones stop ringing and the office hubbub finally stops and you can hear yourself think. Maybe sitting in your garden listening to the insects and aeroplanes pass overhead. Or maybe it’s that first 5 minutes of waking before the baby starts howling. Whatever it means to you the point is silence isn’t really silent. Something is always making a sound even if it’s a leaf rustling in the wind or a cricket singing.
In the African bush night time silence is deafening. Just before sunset there is a rush of activity. The day shift starts looking for a place to spend the night whilst frantically searching out that last mouthful of food. Young banded mongoose are scolded into their burrows by older siblings. Antelope take a drink before heading to thicker cover. Francolins are calling out their staccato calls whilst sandgrouse flock to drink. As the sun sets and darkness looms everything quietens down, the last to make a noise are the guinea fowl who wait till it is just dark to, one by one, barrel up to adorn their favourite roosting trees like giant Christmas baubles. They finally settle down, and the nearby baboons stop squabbling and there is a moment’s peace before the night shift takes over.
The Scops owl is first with its ‘poop poop poop’ call sounding almost like an insect. Then the night-jars join in. A distant rasping bark and the jackal are off calling ownership of their territory. They stop suddenly and a moment later there it is, the slow wo-oop! Woo-ooop! and the hyena clan are declaring they are up for business.
There has been no respite to the constant noise of the African bush during this transition between day and night; a seamless mix between the two sound tracks. As the evening wears on and the night shift are out hunting in earnest it gets quieter. If you are lucky enough to experience this it is unforgettable. The silence is thick, it hurts your ears and you want to shake your head to clear it. You are straining to hear anything out there in the blackness and your senses have you on high alert, never mind that you are in a vehicle your primal instinct knows this is Africa and beasts roam that want to eat you.
The only sound is a cacophony of insects and it is this that gets in your head, it is a relief when a spotted eagle owl calls breaking the pitch and giving you perspective again. Staring into the blackness you see a shape move , you can’t make out what it is, then comes a noise that goes right through you, a guttural, low sawing sound, a leopard is calling broadcasting its presence using the ground as a sounding board. He walks out in front of you, pauses for a moment, then strides off purposefully into the night.
The silence of the African night is palpable. You could slice it with a knife. It is so full of promises of wonderful animal encounters that I never want to sleep. It’s my favourite sound of silence; what’s yours?
Of all the antelope that we classify on snapshot Serengeti the eland is one of the most distinct. Its massive size, heavy set horns and swinging dewlap lends it a bovine appearance yet it is an antelope – all be it Africa’s largest. A member of the Tragelaphini family or spiral horned antelope the eland is closely related to kudu, nyala and bushbucks.
There are two species, the common eland (Taurotragus oryx) we are familiar with in the Serengeti and the giant eland (Taurotragus derbianus) found sporadically in woodland savannah across Central and West Africa. One thing to get straight is that giant eland are on average less bulky than their common cousins, the ‘giant’ refers to their horns.
At close to a thousand kilograms in weight a fully grown male eland equipped with a fortified neck and viscous hefty horns could prove a lethal adversary. Perhaps it is unsurprising then that most male interactions are highly ritualised and the real fighting only really occurs between males of near equal stature. It is an unusual trait in male eland that the neck, shoulders and dewlap continue to enlarge as the animal ages. They develop tufts of wiry hair on their foreheads and noses and a strange clicking in their knees develops that is audible quite some distance away. I remember once sitting in a clearing in the bush and hearing what sounded like multiple people cracking their knuckles whilst moving closer towards me. I could not even begin to imagine what was fast approaching me and began to get a little nervous, looking around for a tree to climb. I heard nothing else but the odd branch moving until out from the edge of the bush appeared a small group of eland. Much to my relief it was precisely these knee clicks that I had heard.
Although not a particularly fast running antelope eland are noted to be extreme jumpers. They are capable of leaping over three meters high from a standstill which to me puts to bed any lingering doubts that they are antelope not oxen.
As many of our snapshot images attest to they are often found in quite large herds, congregations 100’s strong are not unheard of. But all the same there is no real structure to the group. Herds can comprise all males, all females or mixed sexes and ages. They are highly interchangeable and very few bonds are formed. Even the sacred mother and calf bond is tenuous in eland society. Calves form crèches when they are a few days old and prefer to hang out away from the adults. They only suckle once or so a day and that can be the only time spent with mum. Female eland will band together in defence of their young but as they are often out of sight of the youngsters this doesn’t happen too often. Instead young eland grow fast attaining 450kg in their first year.
Although life seems good in these juvenile gangs and generally eland are long lived, mortality can be high in youngsters. Whilst studying leopard in South Africa we found eland was a common prey item, in fact we discovered three kills within a month of eland less than six months old and those were just the ones we found. Lion and hyena are also known to take their toll. There is no real synchronised birthing in eland herds with young born at anytime. I guess this means there is always a slightly younger, less savvy, youngster in the crèche that is easy prey for predators.
Next time you find an image of an eland herd have a close look to see if you can work out if they are females (smaller with more slender horns), males or if perhaps it is a crèche.