Here’s a great post by the BBC about some genetic work that has just been done to shed light on the evolutionary history of lions. Apparently, it’s a bit tricky reconstructing lion history due to the fact that they don’t fossilize particularly well (generally not conducive conditions in lion habitat) and that humans create giant holes in the record by wiping out entire sub-population.
However, from genetic analyses of living lions and museum specimens, these authors have determined that there are two evolutionary groups of lions – those in India and Central/West Africa and those in Eastern/Southern Africa. This happens to have some interesting implications for lion conservation and reintroduction — check out the article!
The story of how reintroduced wolves transformed Yellowstone is now well known. According to the story, wolves scared elk away from the riversides, which allowed the willows and aspen to recover, allowing beavers to come back because they had home-building material big enough to use, and the beaver dams restored the health of the watershed.
I remember reading this story in college. I was sitting at a computer in UVA’s Alderman Library, digging up articles for a class presentation, when I stumbled on the now highly controversial article, “Wolves and the Ecology of Fear.” It blew my mind: right then and there, at the beginning of my last year of college, I knew I wanted to study how predators drove ecosystem dynamics.
It’s a beautiful story, and one that changed the trajectory of my career. And it’s one that’s been very hard to let go of, despite mounting evidence over the last decade that this story might not be more than a myth.
I had the good fortune of meeting Arthur at the Ecological Society of America talk last summer. I was a big fan of the work that he’d done, and that of his Ph.D. advisor, Dr. Matt Kaufman. But I didn’t envy either of them as they stepped into the fire of trying to take down what has become a beloved, monumental, epic tale. There’s no doubt that behaviorally-mediated trophic cascades do exist, and that predators can have profound influences on ecosystems, but the long-standing poster child for this simply isn’t real.
If you do one thing on your coffee break today, read his piece. While I could summarize the debate here, I couldn’t begin to do justice to Arthur’s eloquent argument.
Scratch that. If there’s one thing you do today, read Arthur’s piece. Not only will it make you think about wolves and ecology, but it will make you think about what nature we save, why we save it, and why that matters.
Season 7 is up and running, and we’re already running into some interesting critters!
No, that’s not a house cat wandering through the middle of the savanna. If you check out the gigantic ears, it appears that we’ve caught sight of a melanistic serval! Melanism involves a genetic mutation that causes the development of dark pigments in the skin, like a reverse albinism. For comparison, these guys normally look like this:
According to our field assistant, Daniel, the serval population is booming in the Serengeti at the moment. Perhaps with so many animals, it’s not entirely unexpected to find one or two odd cases like this.
Let’s see what other interesting finds pop up in the latest season of Snapshot Serengeti!
Watching animals in the wild, I’m always amazed at their power, agility, stealth, grace…I could go on. Even our household pets seem way more adept at maneuvering in this world than I feel on a daily basis.
And so this site
makes me giggle because it reminds me that I am not the only one who sometimes has trouble making her feet land where they are supposed to. Although I have to admit that if I ever tried to leap upwards ~10x my height, it would end far less gracefully than for these four-legged acrobats, who always seem to walk away completely unscathed.
This series of photographs documents a stand-off between two male lions — a younger male attacking? defending against? an older male. Interestingly enough, at the last minute, a pair of lionesses jump in and join the young male in evicting his older competitor.
In lion societies, males leave their birth prides at a young age and join together with other males, forming coalitions. These groups, which vary in size from 2-9 individuals, range across territories and attempt hostile takeover of established female prides from other males. While it may seem that the only obstacle to taking over a pride is the coalition of males who have already set up shop, it isn’t always in the females’ best interest to stand by passively and the males duke it out.
A group of male lions’ first order of business upon gaining tenure of a new pride is to off all the females’ dependent offspring. Loss of cubs brings females back into heat sooner, giving the new males a reproductive incentive to commit infanticide. The female, on the other hand, suffers an immediate loss in fitness — all the reproductive effort invested in her cubs is gone! Females have evolved a number of ways to reduce the risk of infanticide by males, including behavioral strategies such as banding together with their current coalition to stave off intruders. Is that what’s going on here? Perhaps, perhaps not. The female-defended male looks fairly young the be in this type of a situation. Cub loss, however, is an important factor to keep in mind when considering sport-hunting of mature male lions. The effect of removing a resident male is removed may cascade through his social group, leading to additional deaths within his pride when new males move in to his vacated niche.
Grinnell, J. and K. McComb. 1996. Maternal grouping as a defense against infanticide by males: Evidence from field playback experiments on African lions. Behavioral Ecology, 7(1): 55-59.
Packer, C., Scheel, D., and A. Pusey. 1990. Why lions form groups: food is not enough. American Naturalist, 136(1): 1- 19.
If you’ve got the time to sit down for 15 minutes and subject yourself to some truly awe-inspiring photography, check out this TED talk from the documentary film-making couple, Beverly and Dereck Joubert as they recount their adventures in Africa interacting with big cats and their big personalities.
I have just got back from a short (too short!) trip to Costa Rica. I wasn’t sure what to expect from this world famous eco destination but I decided to bring my camera trap with me on the off chance I would be given permission to set it up and capture something new, for me anyway.
My time was split between two distinct ecosystems, lowland rainforest of the Caribbean slope and dry forest of the Guanacaste/Nicoya peninsular. I stayed in protected areas and reserves so the chances of mammal activity was there, unfortunately I had only two or three days in each place which limited the chances of capturing anything somewhat. Hardly scientific I know but I was curious to see what might be out and about after I was tucked up in bed.
Now I am used to the African bushveld, a dry-ish, semi wooded, semi open grassland environment with a sandy substrate. It is easy to see where animals are frequently passing from trampled vegetation and tracks. Placing camera traps and getting results was not too hard. Costa Rica’s rainforests on the other hand was a challenge. The vegetation was thick, lush and resilient to animal passage and finding tracks in the dense leaf litter was impossible. Costa Rica’s dry forests where just as bad. It was the dry season and the trees had lost all their leaves…big leaves that made a thick carpet on the ground covering any tracks and trails.
Needless to say I did not get too many results but taking my time frame and lack of local knowledge into account it is amazing that I got anything. All the animals were at least new to me so gave me a great buzz.
Of the animals I captured peccaries, a type of pig where the most common in the rainforest followed by crab eating raccoons in the dry coastal forests. I captured 1 agouti, 1 paca, 1 probable grison devouring my camera and the most exciting of all an ocelot. Typically the ocelot was the very first capture on the first night. Staying at the Selva Verde lodge I had the help of the resident guide, Ivan and we placed the camera near to the river. I think he was just as thrilled as I was to get an ocelot despite their being the most common of the neo tropical cats.
I hope you enjoy this short video clip, you can see if you look closely that the ocelot is carrying something in its mouth, prey?
I’m in the process of writing up some *really* cool camera trap results from Seasons 1-6, and plan to share them here next week (as soon as I make them pretty). It would never have been possible without your guys’ help. But in the meanwhile, this just aired again on TV, and thought you might enjoy a bit of a break! They talk about the camera traps a bit ~33 minutes in.
As you all ready know Snapshot Serengeti’s thousands of camera-trap images are part of an ongoing study into predator interactions by Ali. There are few projects that use camera-traps as extensively as Snapshot Serengeti and of course Ali has her hands full analysing the bits relevant to her. The cameras work around the clock recording details of daily and nightly life in the Serengeti and do not discern between the stuff Ali does and doesn’t want. That’s why, Ali’s sanity aside, they are such perfect tools. Those same cameras providing Ali’s data could also be the basis of a future ecologist’s research.
One of the most striking asides for me is the case of the giraffe and the oxpeckers.
Oxpeckers are small birds that feed on ticks and other parasites that they glean from the bodies of large mammals. Most usually they are seen riding along on large mammals such as buffalo, wildebeest and giraffe whilst they search their hosts for ticks or open wounds. This in itself is not an unusual occurrence and most of you will have hit the bird /other button with these guys. Much more unusual are the shots of giraffe at night time with these birds using them as roosting spots. There are two species of oxpecker, the red-billed (Buphagus erythrorhynchus) and the yellow-billed (Buphagus africanus) both of which are found in the Serengeti.
According to research carried out by M. Stutterheim and K. Panagis that looked at the roosting habits of both species the red-billed oxpecker roosts in trees but the yellow-billed was often found roosting on their preferred host species. Apparently red-billed oxpeckers feed on a wide range of host species where as yellow-billed oxpeckers are much more picky preferring buffalo and giraffe. It is thought that the habit of roosting at night on their favourite host species is an adaptation to save the birds time looking for the right animal the following day. Given that buffalo and giraffe are prone to walking large distances this is probably very sensible.
From most of the images we have of oxpeckers on giraffe at night it is hard to tell which species they are but there are one or two where you can see the tell-tell yellow bill confirming that they are indeed yellow-billed oxpeckers. The images also show that the birds seem to prefer settling between the hind legs of the giraffe. This must be a nice warm spot in winter and keeps them safe from any nocturnal predators.
Perhaps the behaviour is not so unusual after all but rather little documented. Getting photographic evidence of birds at night on mobile roosts is obviously not easy. Looks like our camera-traps have excelled themselves again.
In processing Seasons 5 and 6, I recently stumbled upon a bunch of video files amongst the stills. You may recall that while we have our cameras set to take still images, every once in a while a camera gets accidentally switched to video mode. Then it takes 10-second (silent) clips. Most of these are “blanks” triggered by grass waving in the wind. But every once in a while, we get ten seconds of animal footage. Here are some from Season 5.
And, what do you think this is?