Maybe long necks can be adaptive for something other than foraging?

Everyone can probably look up the origin of the word Galapagos, which was given to these islands based on the tortoises found here. The giant tortoises (not all of them, mind you) have saddle shaped shells, from which the term galapagos comes from. On top of that is the variance in shell morphology seen in turtles from island to island. Apparently, although they differ tremendously from island to island, the consensus is that there are ~11 (sub)species of the giant tortoise. I am still trying to wrap my head around which is which, but we see them every day here at the research station. Breeding (or attempts at breeding!) are common. Tortoise grunting can be heard from the bushes all around us, along with the ‘fingernails on chalkboard’ sounds of claws on shells.
I never thought a tortoise could grin, but here is a pretty cheeky male:


Same male demonstrating some rather intimate face-to-face contact with his less than impressed mate. It does show that a long neck can be useful for something other than that hard to reach plant.


2 thoughts on “Maybe long necks can be adaptive for something other than foraging?

  1. Hi Glenn,
    That is one cheeky tortoise! Excellent photo. Has anyone investigated the potential role of the saddle-shaped shell for combat? (True, I'm on a competition kick after watching the pugnacious finches.) This morning I watched a pair of male tortoises “fight”, which consisted of an uninspired hiss, but also a quick raise of the head (quick for a tortoise, that is). It seems that the individual who raises his head highest is the winner. These guys were fighting over food, but it could also be for mates. I think the individuals in the picture above show sexual dimorphism, which would suggest sexual selection via male-male combat…


  2. Nice idea, Ray! I was being rather cheeky myself with the post, but perhaps he who raises his head highest is also prepared to peek his head over the saddle top. Multi-cause, multiple outcomes. How do we ever discuss adaptation when nothing exists for only one reason?


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