The REAL Reason Giraffes Have Such Long Necks

Have you ever been told that the reason giraffes have such long neck is that they evolved to eat leaves on tall trees? Well, you've been lied to. The real reason (surprise, surprise) is sex and mating:

The latest theory – and it's a surprise this hasn't come up before, given biologists' fixation with it – is that the long necks are the result of sexual selection: that is, they evolved in males as a way of competing for females.

Male giraffes fight for females by "necking". They stand side by side and swing the backs of their heads into each others' ribs and legs. To help with this, their skulls are unusually thick and they have horn-like growths called ossicones on the tops of their heads. Their heads, in short, are battering rams, and are quite capable of breaking their opponents' bones.

Having a long and powerful neck would be an advantage in these duels, and it's been found that males with long necks tend to win, and also that females prefer them.

The "necks for sex" idea also helps explain why giraffes have extended their necks so much more than their legs. If giraffes evolved to reach higher branches, we might expect their legs to have lengthened as fast as their necks, but they haven't.


Previously on Neatorama: 30 Strangest Animal Mating Habits

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i thought they had long necks so they could very cutely stick their heads out the windows in Noah's ark during the great flood. damnit, bible school failed me again.
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While I don’t blame you for arguing your point considering Alex’s misleading intro, it appears that you didn’t read the article at the link. The researchers actually considered this by creating a theory that incorporates how different variables may have contributed to the giraffe’s long neck as an alternative to the current popular “strict adaptationism” theory. They even used an exaptation example of the giraffes’ ancestors initially developing longer necks to reach higher leaves, but then taking on more of a sexual selection role.

Regardless, there are some examples where “strict adaptationism” makes perfectly logical sense, such as the guts of ruminants being suited to digest cellulose.

I hope you still find it acceptable to at least speculate and develop possible theories (while making allowing for error) as to how certain physical features may have evolved in organisms rather than just give up because we will never know for sure.
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Doesn't anybody ever read Stephen Jay Gould or Niles Eldredge?? Strict adaptationism is not supported by empirical evidence; it's a collection of plausible "just so" stories (Gould's phrase, not mine!) Yes, they make good media sound bites, and they are currently fashionable, probably for that reason. It's fun to sit around and come up with stories. It doesn't sound as good to say, "We really don't know. The giraffe may have a long neck for an adaptionist reason, or this feature may have come about as an exaptation, something that evolved who-knows-why and was later adapted for its current use." One day soon, this line of thought will look every bit as stupid as when Freudian theories were advanced to explain absolutely every facet of human behavior.
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No No, the real reason is that a giraffe's brain runs mostly on hydrogen (as everyone knows) and being lighter than air, this causes the giraffe's head to want to float. Over the years the constant pulling on the necks has forced the animal to grow long neck to remain anchored to the earth.
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