A hyena in a quandry

Anthony spotted something interesting, told us that he was going to move, and took off rapidly. I saw a line of dust raised by something running across the plain in the distance. Father of Niece Tatu was quick. “Hyena”, he told us. Another line of dust followed the first. The Family was looking at them through her binoculars. The road curved around and by the time we had come close to them, they had crossed the road and were running away from us. I took a photo, but it wasn’t very good. But a third one came running from the same direction. This time I was ready for it. As I took photos, this one did something more interesting than just run. It came to a halt, spooking a bunch of zebras. It wasn’t interested in them. It looked around, looking a little lost. It spent a long time looking around, and then turned and loped back in the direction it had come from. What just happened? I have the story in the slideshow below, but can’t figure out why the hyena did what it did.

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The hare wanted to steal the hyena’s cows. So he made up a story about a stone and a panga which had to be delivered to someone far away, and sent the hyena off on the errand. While he was gone, the hare stole the cows, cut off their tails and stuffed the tails into the ground. When the hyena came back without being able to find anyone who wanted the stone and panga, the hare told him that the cows had got stuck inside the earth. They pulled at the tails together, and they came out without the cows. The hyena did not suspect that the hare had stolen his cows.
—Kikuyu folk tale

The spotted hyena (Crocuta crocuta) once ranged across Asia, Europe, and Africa. As habitats were remade by humans over the centuries, it became extinct over most of its range. It can now only be seen in protected areas in Africa, although it is not yet classed as endangered in any way. Of the many interesting things about spotted hyenas, what intrigued me most is their complex but hierarchical social organization. They form large clans, with female dominance. Reversing the organization of chimpanzee troops, even the lowest ranked female outranks the highest ranked male. Rank is not maintained by aggression or size, but through networks of allies. Rank is passed on to offspring, so that the daughters of the highest ranked female come higher in rank than other females. Field studies find that hyenas are able to recognize fairly distant relatives, and may act less aggressively towards them. Quite contrary to this is their behaviour towards siblings, which is extremely violent, with dominant females killing sisters soon after birth. Throughout the animal kingdom, the biggest driver towards intelligence that we see is a complicated social behaviour. The hyena is no exception; some believe that it is more intelligent than chimpanzees. Hunters’ stories quoted as evidence of this have been partly verified by laboratory observations on learning and cooperation. It seems that its traditional reputation of being stupid, evidenced in many African folk tales, is quite mistaken. The little drama that I observed on the dusty plains of Amboseli national park was very likely a part of a long story of cooperation and rejection.

Kestrel

I had a wonderful sighting of the female kestrel whose photo is featured in this post. It sat on a dry tree in the middle of the Thar desert for a long time, scanning the surroundings. I suppose it was looking for jirds or other rodents to eat. I loved that sideways glance with which she dismissed me as being of no consequence. I had no choice but to slink away.

The common kestrel (Falco tinnunculus) seems to be really common, being found over all of Asia, Africa and Europe, except only Siberia and the Sahara, Gobi, and a part of the Thar desert. Interestingly, it is found in the more inhospitable parts of Thar. One can speculate why. The common Kestrel evolved about 2 million years ago, after the Sahara and Gobi were formed. But the Thar desert developed later, so the Kestrel must have just acclimatized to the change. I wonder how this hypothesis could be tested.

The male differs from the female most visibly in the colour of its head: it is pale unlike the brown of the female. There are other differences in plumage as well: the markings are less prominent on the male. Interestingly though, it is in size that there is a very remarkable sexual dimorphism: the male is smaller. I’ve written about how gender politics shapes the bodies of raptors which pair bond. The combination of relatively drab colours and smaller size falls directly in line with the argument which I had explained at length: that this has to do with the female tending the brood while the male hunts for the family. I was happy to see that this has been put to observational test and the hypothesis does seem to hold.

Aggression

In the sambar deer, dominant stags fight with others to retain control of hinds. The losing stags are pushed out of the herd. The IUCN red list says that sambar are vulnerable due to habitat loss across its full range. This includes southern China, south-east Asia and India. However, it is possible that there is a cryptic difference between the Indian population and the rest, which could split this in future into two species. If so, then the reasonably well-managed Indian national parks could convert the western population into the "near threatened" category, and the Chinese and south-east Asian population could then be plausibly classified as endangered. Since sambar is the main prey of tigers, it is impossible to stabilize tiger populations without first creating conditions for sambar to multiply.

In my lifetime sambar has become almost invisible outside of national parks. We saw few herds of sambar inside Pench national park this time around. I had only a couple of glimpses of a stag the fully developed antlers you expect to see this late in spring. We saw one defeated male grazing by itself in the shade under some trees. If you look carefully at the featured photo you’ll see that it has only one of the antlers. The other was broken off near the base.

Observations over many years reveal that the sex-ratio in sambar is heavily tilted towards femles. I also remember seeing, a few years ago, a sambar female in the wild who was so old that she was slightly arthritic, and her coat was greying. I’ve never seen a stag that old. Is it that stags are more vulnerable to predation? Or could it be that aggression within the species is such a source of stress that it kills off males. Looking at the male with one antler, we could not dismiss this possibility.

Later, at a waterhole, waiting for tigers to emerge, I overheard a conversation in a nearby jeep. One man said he had seen 45 tigers. A companion replied that he had seen only 25, but then, he started recently. A third chipped in to say that he writes down details of every sighting, and that he thinks he must have detailed entries on about 30. The Family nudged me to draw my attention to this bit of male aggression in Homo Sapiens. We are so lucky; I cannot imagine that stress at not seeing tigers in the wild can kill us.

Sexual politics in the jungle

A couple of days ago I wrote about how gender shapes chicken and their ancestral relatives, the red jungle fowl, Gallus gallus. Males fight each other to try to monopolize breeding with groups of females. This leads to larger sizes and extreme combativeness among males. The female is solely responsible for rearing chicks. Not only is she smaller, she is also drab coloured, so as to be less noticeable. The pattern of males being larger and more aggressive than females is also seen in other animals with similar social organization, for example, spotted deer (Axis axis), lions (Panthera leo), monkeys such as Northern Plains Langurs (Semnopithecus entellus). There are conjectures that sex-linked size and aggression in Homo sapiens is also due to social organization of this kind when our ancestors roamed the grasslands of Africa.

Thurber's cartoon

One of the more commonly visible birds in Pench national park was the Oriental honey buzzard (Pernis ptilorhynchus). The first one we saw was sitting on a nest, probably incubating a clutch of eggs (featured photo). The Family saw it instantly since she was looking through her new binoculars. I was peering through my camera, and I saw the nest but not the bird, until I zoomed the image. We kept seeing these birds through the next couple of days: flying low over us, sitting on a branch, diving into the grass. Once I photographed it on a branch (photo below), just before it dived into the dry grass below the tree. I could see it wrestle and worry something in the grass, so I waited for it to emerge with something in its beak. Unfortunately it appeared without anything and flew away.

Male oriental honey buzzard in Pench National Park

This was the breeding season, and clearly the intense activity was related to that. The females sat in nests, either brooding over eggs, or looking after hatchlings. I guessed that probably the males were doing most of the flying. Later reading told me an interesting fact: apparently in this, and many other species of hunting birds, the male is smaller than the female. The reason again seems to do with social organization.

In honey buzzards and other raptors, a male and a female bond as a breeding pair. The pair cooperate in raising the young. The mother spends more of her time in the nest, while the father spends longer periods foraging for the family. The wing span of male and female honey buzzards is about the same. So the smaller body of the male makes it more manoeuvrable, and a slightly better hunter. The same holds true for other hunting birds. Interestingly, those which hunt faster prey have relatively smaller males. Vultures show almost no size difference between the sexes.

Traumatic beginning of adulthood

Interestingly, all birds abandon the young once they are grown. This is again a theme that recurs throughout the animal kingdom, even among H. sapiens. To get back to our main theme, the full story of sexual dimorphism among birds may be more complicated than this. Studies show that strongly coloured males and drab females arise in bird species where the male tries to dominate a breeding group of females, but a significant fraction of the offspring are not the dominant males. This is extreme sexual politics. However, the mutually supportive roles of the two parents in the cooperative rearing of offspring prevents sexual politics from arising amongst honey buzzards.