Tortoise sex

Sat, 2007-11-17 14:01 by hcroze

Mating tortoises
Mating Tortoises

I have no elephant news this week (have been in Nairobi, unable to fly to Amboseli because of rain here), but I did happen to glance out of my study window into our Muthaiga garden and was shocked to see two of our seven Leopard Tortoises (Testudo paradis) in flagranti (see image; hope your Parental Guidance filtre doesn't expunge it).

It was the climax, as it were, of an even funnier scene in which one of the smaller males (not pictured) had plowed under the large one and in a nifty Tae Kwon Dao manouvre nearly upended his larger rival.

After a victorious pause, though, he stumped off, perhaps realising that she really did present an unsurmountable logistic problem for him, being some five times his bulk. Or was it, as with elephants, female choice? Anyway, the big male (pictured) who is 45cm (18 inches) stem to stern, resumed his courtship and apparently succeeded.

Notice his open mouth. During the mounting and mating, the otherwise totally silent animal vocalises lustily, with a repeated nasal "Heh... heh... heh..." This probably has the function of signaling his intent and perhaps serving as a stimulus to override her natural reaction to move away from something scrabbling around her backside -- rather like an eostrus female elephant's response to a courting bull elephant laying his trunk along her back. In the case of the female tortoise, the audio signal is probably crucial to stop her in her tracks. Mating, if it happens, lasts only about a minute, usually interrupted by the female moving off and getting back to her feeding.

Since we're on tortoises, let me quieten you down from the excitement of the previous paragraph with a quote from my book, Pyramids of Life, page 104:

There are two paradigms of the Jurassic that persist in African ecosystems: the crocodile (see page 181) and the tortoise. In fact, the ancestry of the tortoise and its close relatives the sea turtles and fresh water terrapins is older even than that of the inhabitants of Jurassic Park, stretching back over 200 million years to the mists of the Permian. It is likely that tortoises looking much like they do today were plodding about under the feet of dinosaurs, munching just about everything encountered from dead meat to living vegetation. Down through the ages it has been buffered from predation by its shell, an ingenious box made from a fusion backbone, ribs and breastbone.

When form follows function without frills, you get some classic designs that persist through changes in fancy and fashion. Incongruously, images of tortoises and Volkswagens spring to mind — low-key time travelers that have surpassed many in the race.

Today’s leopard tortoise, one of the dozen African species, is a strict herbivore that stays within a one or two square kilometre home range throughout its several decade life span (in captivity they have reached 75 years old). Its laid back aspect is more than shell deep, since even its muscles are designed to contract at rates 50 to 100 times slower than those of a mouse or a frog. Conservative, endearing and a little bit boring, its main claim to fame is being a living icon to the I Ching aphorism, “perseverance furthers”.

Arid and semi-arid lands animals usually burst into sexual activity with the onset of the rains and rapid growth of primary production. Nairobi has had a fair short rains so far (unlike Amboseli, see Cynthia's blog on the subject), with about 60% of the 50-year average so far and more on the way. The suburban tortoises of Nairobi have an additional nutritional input in the form of the myriads of Jacaranda flowers that drop onto the lawns each November. Our tortoises just love the spicy sweet taste of the flowers and plow tortoise-width swaths eating their way through the carpets of blossoms.

Note: if your search engine has drawn you into this blog because your keyword was not 'tortoise', I do apologise for wasting your time. ... naughty, naughty!

Tortoise contemplates blossoms
Tortoise contemplates blossoms

Tortoise eats blossom
Tortoise eats blossom