By Emma-Louise Nicholls, on 18 November 2013
When people come into the Grant Museum for the first time I frequently hear the question “Is it just this one room?” When I say “Yes”, I always hastily follow it up with the factoid that we have more zoological specimens on display in ‘just this one room’ than in the whole of the Natural History Museum in South Kensington. It’s not that I’m trying to start some rivalry (although the idea of science nerds and museum geeks having a show down does amuse me) but the point I am making is that we display our specimens in such a way that you have to look with your eyes rather than your feet. Due to the density of our specimens, it inevitably means that some will get frequently overlooked, and I want to bring one such, huge, specimen to your attention from the back corner of the Museum. This week’s Specimen of the Week is…
**The Galapagos giant tortoise**
1) The Galapagos giant tortoise is… GIANT. If you’re a tortoise. And maybe even if you’re not. The word Galapagos actually means tortoise (which you would know already if you followed us on Twitter) so this animal is in fact called a tortoise tortoise. It is, unsurprisingly, the largest tortoise in the present day with a carapace that can reach up to a metre and a half in length.
2) There are a number of subspecies of Galapagos tortoise due to populations becoming isolated on separate islands with different habitats and environmental conditions, leading to speciation. Although the exact number of valid subspecies is under debate, they can be crudely divided into two types. Subspecies with a ‘domed’ carapace occur on larger, wetter islands within the Galapagos island chain. Smaller subspecies with a ‘saddleback’ carapace inhabit the smaller islands with drier vegetation. To an evolutionary biologist, this is pretty much orgasmic levels of excitement.
3) The Galapagos giant tortoise has an energetic, non-stop, fast-paced life, largely consisting of grazing on grasses and cactus fruits. When the rainy season arrives it gets even more chaotic in the life of a giant tortoise, as they then add ‘wallowing in shallow pools’ to their daily itinerary.
4) Slow and sedentary their lifestyle may be, but male Galapagos giant tortoises actually become territorial during the mating season. This may take some imagination, so let me help you visualise it. They don’t rut like stags or claw each others fur out like tigers, they have a much more dignified method of sizing each other up. They do it literally. They stand up as tall as they can on their legs, with their head held as high as their neck will allow. The taller tortoise, is the winner. Total bloodshed and carnage.
5) Once the tallest male has been established and, errrr, nature has ‘taken its course’, the female will lay a clutch of between two and 16 eggs. The nest is a hole which the female digs in the sandy ground, which she then covers over with soil and leaves to protect and incubate the eggs. Four and a half months later, the smallest giant tortoises you’re likely to ever see will hatch. The most impressive thing* about the Galapagos giant tortoise is their longevity. They are one of the longest-lived of all known vertebrate species alive today, with the oldest known individual passing away at the grand old age of 152.
Emma-Louise Nicholls is the Curatorial Assistant at the Grant Museum of Zoology