Showing posts with label tracks. Show all posts
Showing posts with label tracks. Show all posts

Wednesday, April 14, 2010

Telltale footprints

While searching for Bugbears today, I came across these tracks.

They followed the road for about 200m before veering off into the bush towards the dam.

At first I was completely baffled. They look like crocodile tracks but something isn't right. The curving line you can see on the left was made by the crocodile's tail, swinging back and forth as the animal walked. And on either side of the tail line you can make out the reptile's foot prints. But why are there two gouged lines?

A crocodile with two tails? Two crocodiles walking in single file?

It took me a while to figure it out, and then I felt stupid for not realising immediately: the crocodile was carrying something which was scraping along the ground.
It's not unusual to find crocodile tracks here, because the animals use the roads to move between rivers and dams. They can travel long distances, especially to exploit to temporary water bodies.

This dam in Bugbears' territory is about 2 km from the nearest water, and it dries up completely each winter. But within 24 hours of it refilling (at the start of the wet season), a large crocodile always moves in.

If disturbed far from water, crocodiles pursue the strategy beloved by tortoises and chameleons everywhere: they freeze and try to blend into their surroundings. Their camouflage is surprisingly effective out in the bush (and I've got the scars to prove it) but less so on the road. Several times I've come across large crocodiles stretched motionless across the highway. I think, 'Oh my God, it's been run over!' and start madly worrying how on earth I can get an injured crocodile to the vet. But as soon as the traffic is gone, the croc just gets up and marches off. And you'll be amazed the length to which motorists will go, NOT to run over a 3 m crocodile!

I don't know what today's crocodile was carrying at Bugbears, and I don't really want to think about it. The photos below will help your imagination conjure up images as vivid as my own. These pictures were taken by visitors to Kruger National Park (which is just next door) and posted on the Public Sightings Gallery at the South African National Parks' website. Check it out: it's amazing what people get to witness.

Baby hippo. Photo by Yolande Oelsen.


Fish. Photo by Peter Winnan.


Warthog. Photo by Bernard Steele.

Saturday, April 3, 2010

How to find a mongoose


Regardless of how much you love your job, there's always some aspect of the work that's tiresome, frustrating or just plain disheartening.

For me, it's finding the mongooses.

Take today: while everyone else was happily munching hot-cross buns or overindulging on chocolate, I was out there struggling through thorn-thickets, hour after hour, totally failing to find my mongooses.

I've got nothing against radio-collaring study animals, but dwarf mongooses are – well – dwarf. The small collars they need have a limited battery life, so the mongooses need to be recaptured every few months. As a biologist working with wild animals, I believe that if it's possible to obtain your data non-invasively, you should, even if it means you're sometimes inconvenienced.
Just at the moment, I repeat this mantra to myself frequently. You see dwarf mongoose groups have territories of 30-40 hectares, and while it's fairly straight forward to find them eight months of the year, in the summer wet season, when the bush transforms into a lush, tangled jungle, the 'inconvenience' sets in.

So how do you find a 3-inch-high mongoose in 40 hectares of bush?
You get up early!
The mongooses sleep in the ventilation shafts of disused termite mounds, and each group has about 30 of these sleeping mounds in its territory. In the cooler winter months, the mongooses sleep late and lounge around their refuge for hours, soaking up the sun, romping in play and grooming one another. To find them, I simply have to check each of their refuges first thing in the morning.

Latrine left by Bugbears at their overnight refuge.

Even if the group has already set out foraging, I still know where to start searching because they considerately leave behind a latrine at their sleeping place. They are also very keen on scent-marking, so whenever the group passes a scent-marking site (and they have about 40 of these scattered through their territory), they'll smear pongy anal secretions on the logs and rocks, and leave a dropping or two. By checking these 'message posts' (all plotted on my GPS), I can track where the group has gone.

Keni contributing to Bugbear's latrine.

But in summer, everything goes pear-shaped. Firstly, the mongooses get up very EARLY. The moment the sun edges over the horizon, they come tumbling out of their mound, climbing over one another in a flurry to latrine, and hurrying off to forage. With daily temperatures reaching the high 30s or low 40s (Celsius), they can't afford to linger - by 9am they'll have to forgo foraging to lie about in the shade. So although I get up at 4 am, I'm usually not able to find them at their refuge. And the difficulties don't stop there. In summer the dung beetles are active. These poxy, little varmints come buzzing in the moment a mongoose defecates. They tussle over the droppings, gathering them up and rolling them away into the undergrowth. Within 10 minutes there is no trace of the latrine.

So I'm left tramping back and forth through the mongooses' overgrown territory, disconsolately sniffing at rocks and feeling thoroughly inadequate!


A dung beetle doing its dastardly deed.


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