Colours of Wildlife: Potto
Created | Updated Apr 24, 2016
Potto
Willem is a wildlife artist based in South Africa. He says "My aim is simply to express the beauty and wonder that is in Nature, and to heighten people's appreciation of plants, animals and the wilderness. Not everything I paint is African! Though I've never been there, I'm also fascinated by Asia and I've done paintings of Asian rhinos and birds as well. I may in future do some of European, Australian and American species too. I'm fascinated by wild things from all over the world! I mainly paint in watercolours. . . but actually many media including 'digital' paintings with the computer!"
How many of you folks know about this little critter? This is a Potto, Perodicticus potto. Pottos are relatives of bushbabies and only occur in equatorial rainforests in Africa. The potto looks a bit like a bear, but it is indeed a primate, a relative of lemurs, monkeys and ourselves! Pottos are on the small side, with bodyweights ranging from 600 g/1.3 lbs to 1.6 kg/3.5 lbs. They eat mostly fruit and the gum that exudes from the damaged bark of some trees; they also can catch some insects, and will eat ones that are too noxious for most other predators.
Stumpy Fingers and Tails
The potto's body shape is much different from those of the bushbabies. Inside of its fur it actually has a slender body and limbs. It has a much shorter tail than a bushbaby. While bushbabies use their long tails for stabilization and steering on their prodigious leaps, such a tail would be wasted on a potto. Pottos move slowly and deliberately through the trees. They have a movement style much like that of a chameleon, most of the time walking along the tops of narrow branches. They use their hands and also their feet to grasp these limbs very tightly. A potto will cling firmly to a branch with at least two of its four limbs at any one time. It can also hang upside-down below a branch, or hang from both its hands, or both its feet, or from one hand and one foot. During the day they remain immobile, clinging to the underside of a branch. They have special blood vessels in their arms and legs which prevent their limbs from 'going to sleep' from reduced bloodflow during these long immobile periods.
Potto hands and feet are both strongly adapted for firmness of grasp. Strangely, the potto's first finger is reduced to no more than a short stub. It might help with the grip in presenting a knob that can be pushed hard into the surface the hand is holding onto, to secure the grasp. The thumb and other fingers are long. The 'big toe' of the foot is also set off from the other toes, and the foot is almost more hand-like than the hand! The first toe (that is, the one just inside of the big toe) on the foot has a longer, narrower claw on it, which the potto uses to groom its fur with. Like other prosimians (bushbabies, lemurs e. a.) pottos also have narrow, forward-pointed teeth in their lower jaws which form a 'tooth comb' they use for grooming.
Neck spines – and 'venomous' saliva?
One very strange feature of the potto is that it has spines at the back of its neck! Six of its neck vertebrae have pointy tips that actually protrude from the flesh at the back of the neck, being encased in sleeves of skin. When pottos are threatened, they will curl their heads down to their chests and present their backs and necks to the predator. The spikes poking out of the neck might convince the predator that the potto is too prickly a prey!
But pottos probably don't encounter many predators. They are strictly nocturnal, as their huge eyes suggest. In the African rainforests there aren't many nocturnal predators that climb well enough to catch up with a potto. There are some owls, though, but these are rather rare in the rainforests. Pottos, moving slowly through thick vegetation, and having brownish fur, are quite hard to spot, even
during the day.
Apart from this, pottos also have extra-tough skin on their backs, necks and the backs of their heads to protect them if a predator should find them and actually take a bite! But potto defenses are not merely passive. If threatened further, they may bite the predator themselves. And here's the thing … a potto bite can turn nasty fast! Its saliva seems to have something in it that causes inflammation and infection in a wound caused by its bite. But is it venom? The same question occurs about a relative of the potto, the Slow Loris of Asia (which I'll cover sometime here I hope). Does the potto or the slow loris actually have glands that secrete venom, actively transmitted to a defensive bite? For now, it doesn't seem so. It appears that what is in the potto saliva are merely some compounds that are likely to cause allergic reactions. Still, it does appear to function defensively.
Smells Like Curry
Scent is an important factor for pottos. Like other primates outside of the monkey/ape group, they have moist, naked 'snouts' called rhinariums (or rhinaria). This moist surface is very sensitive to odours. Pottos have glands under their tails, that secrete sticky stuff bearing their characteristic scent, which is said to resemble the aroma of curry. They rub some of this secretion on their hands and feet, and so they mark their territory with their scent wherever they go. They also use urine for this kind of territory-marking.
What's more, pottos use their scent on each other. Most of the time pottos will walk about on their own, but actually the females are mostly bonded to males. The male's territory is much larger than those of the females – several females will be in one male's territory, and all of them will be bonded to him. The sexual bond is strengthened by the male visiting each female each day, and they groom and lick each other's fur. In this way their scents are exchanged and the male is marked with that of his females, and the females marked with his scent. Even the neck spines might be involved; as the two clamber over each other, the spiny region of one might touch the genital region of the other, stimulating the flow of the odorous secretions.
Male pottos don't seem to help with raising the babies. Typically only a single baby is born per season. At first, the baby will cling to the fur of its mom's belly, and she'll carry it around as she does her rounds of her territory. When it becomes bigger, she carries it on her back. She may even 'park' the baby on a tree branch and leave it as she goes to forage; the baby is licked well and the allergy-inducing saliva might act as a deterrent. But the baby stays put and tucks its head in between its limbs so that its eyes and ears can't be seen; it becomes a hard-to-spot round, brown lump. The mother will call to her child with a high 'tsik'-sound. Male babies, when fully grown, will leave their mothers' territory and seek their own, while female babies will tend to stay close to their mothers, joining the territories of the several females that are associated with a dominant male.
For now, pottos are widespread, well-camouflaged, and reasonably common. They can live in prime rainforest as well as in disturbed or regenerating secondary forest. They occur all over the rainforest belt of Africa. Close relatives of pottos, and very similar, are the Angwantibos or Golden Pottos, which I will feature here soon I hope.
