Colours of Wildlife: Southern Tree Agama
Created | Updated Mar 16, 2014
Southern Tree Agama
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!"
I've not featured many reptiles here yet. I've lost my reptile guide book! But here is one I can tell you a bit about from my personal experience: a Southern Tree Agama, Acanthocercus atricollis. Its scientific name means 'black-necked thorn-tail'. In Afrikaans we call it a 'Boomkoggelmander' or 'Boomkoggelmannetjie'. 'Koggel' in Afrikaans means 'to mock' so its name means 'tree-living little mocking-man'.
Mocked by a Lizard
What mockery is being made here? These and other agamas do indeed have a mocking habit! The males, especially during the breeding season, develop very bright colours on the head (and often the body too). They are also bold and alert. They stake out territories by visual signals. This being a tree-living species, the signals are given from the vertical trunks of trees. The agama will cling to the bark with his hands and feet, and then do 'push-ups' … pushing his upper body away from the trunk while extending his neck. Then he'll pull himself back flush to the bark, bringing his head in as well, and repeat this maneuver a few times. This causes his bright blue head to bob forward and backward, drawing attention to it. To other agama lizards, this signal, which is visible from a good distance, indicates the presence, alertness and aggressiveness of the male holding the territory. Other agamas mostly display in a similar manner, but on rocks, bobbing their heads up and down. This display can also be given to potential predators, showing them that the agama is on to them. There is definitely an air of mockery to it: 'ha ha, you can't catch me!'
Outside of the breeding season, and in the case of females year-round, agamas are extremely cryptically coloured, mainly in greens, greys and browns. On tree bark they can be almost invisible. But if you should still spot them, and approach, they will scurry up higher into the tree, and also like many other little tree-living things, scurry over to the opposite side of the tree. If you move around the tree as well, they'll spiral around it, always trying to keep the trunk between them and you.
Relatives of Chameleons
Chameleons are some of my favourite creatures and have been featured here before. Agamas are relatives of chameleons, but not nearly as highly specialized. Nevertheless, there is some similarity in their faces, and like chameleons, some agamas can change colour as well. The male southern tree agama becomes more brightly coloured when the weather is warm! Agamas also use colour changes for temperature control.
The agama family is very large and diverse, especially in Asia and Australia. The bearded dragons, frilled lizards and thorny devils of Australia are members of the agama family. Although the agamas of Africa are less diverse, they still include many different species, some of which are spectacular. Most African agamas live in rocky, dry regions. Agamas are also related to the iguanas of the Americas. Essentially, iguanas are the new world counterparts of the agamas of the old world, and have evolved into strikingly similar forms and roles. For instance the Anoles of the new world have similar head-bobbing displays but in their case the display is enhanced by a brightly coloured erectable throat flap. Anoles can also change colour and are sometimes called 'New World chameleons'. A strange exception to the old world/new world divide of agamas and iguanas is on the island of Madagascar which, though close to Africa, has no agamas, but several species of iguana!
In South Africa this is the only agama that regularly climbs into trees. It is easy to identify: it is much larger than any of the tree-living geckoes, and different in shape from chameleons. It reaches a length of 43 cm/17". The other local agamas are all ground-living. Although this one can also sometimes be seen on the ground, it mostly descends just briefly to get from one tree to another, since it lives in open savannah rather than dense forest or woodland. Southern tree agamas show a distinct preference for thorn trees, which are major components of the African savannah. In the Magaliesberg region of South Africa they also often climbed into sugarbush (Protea) trees. They eat mostly ants and beetles. Their distribution stretches into tropical Africa as far north as Ethiopia, but they are absent from the rainforest block and from tropical West Africa. There are ten currently recognized species comprising the genus Acanthocercus, of which this is the only representative in South Africa. There are several other Agama species here, however.
This lizard is one of my all-time favourite critters to encounter in the bush! They aren't found here in my home town of Polokwane, but I do see them around the town a bit to the south, Potgietersrus/Makopane. I often see them there at the game breeding centre, the entry grounds of which has a park of indigenous trees nicely spaced for these arboreal lizards. The breeding males are very conspicuous with their blue heads and yellow to orange backs and tails. They almost seem to be glowing with neon lights! But the cryptically coloured females are also very nice, with their camouflage, giving you a sense of true accomplishment when you manage to spot them! They are amusing to watch with their confident and perky, mocking manners.
This is yet another lizard people like to keep as a 'pet'. Sigh. I really don't like this, these things are just so much better left in the wild! It's very difficult to recreate their habitat and lifestyles in captivity. They are quite social, doing their displays for each other's benefit. They form little groups with a single dominant male and a small harem of females, and also a few juvenile or subordinate males that are not as big or brightly coloured. They are active during the day, but some nocturnal activity has been observed. Like most other lizards they are oviparous, laying clutches of 4 to 15 leathery-skinned eggs. The little agama hatchlings are very cute, with proportionately large heads and bright black eyes! They take care of themselves from the start. These tree agamas can be very common in suitable habitat, and having a very large range in Africa, are certainly not endangered.
