Which means it’s time you got down to a national trust park to get a look at all the randy male deer roaming around, and possibly if you’re lucky, even witness a rut! During the autumn in October time, testosterone levels of red deer all over the country are high, causing stags to fight in order to achieve dominance and win over a lovely harem of females to mate with. This weekend, my boyfriend and I went to Lyme Park in Disley, Cheshire (where Pride and Prejudice was filmed!), in the hope that we would see some sexual selection in action.
As soon as we arrived, we headed straight towards the red deer sanctuary. And, rather than settling down at the first spot (like the self-proclaimed nature photographers stood with their fancy cameras on tripods), we walked around the reserve until we found the perfect spot, situated right behind a male red deer with a rather impressive set of antlers!
Imagine carrying round those heavy, impractical antlers on your head all day and all night. It would be rather inconvenient wouldn’t it?! And exhausting. But for male red deer, it is all worthwhile, because the chances of finding a mate by showing off their big antlers outweigh the energy costs of carrying the antlers round. So quite frankly, in terms of the likelihood of having the opportunity of reproducing, the bigger the antlers, the better!
Having a feature that reduces fitness but is desirable to females is known as the Handicap Principle. This is the idea that because males are able to live whilst having such a hindrance on them, they are exceptionally fit. Therefore females will choose to mate with them so this exceptional fitness is passed onto her offspring. Such features, including the stag antlers are an example of an honest signal. These are features that are a genuine reflection of internal fitness of the animal that has them. The Handicap Principle can therefore be used to explain why these honest signals have led to sexual selection*. For example, in the case of the red deer, they cannot fake the size of their antlers. Males fight each other using them so if they are not good enough they will ‘fail as a male’ in the eyes of a female – she will reject him and he will not be able to reproduce.
But it doesn’t end there! Mating behaviours often depend on a series of honest signals. This is because there are often some sneaky little buggers that can cheat the system. I’m sure if male humans had antlers to attract girls, a lot of them would superglue extra sticks onto them to make them look bigger. So, we can’t really rely on one signal alone to indicate fitness. Therefore stags also do a load of grunting to really get the girls going. The pitch of the grunt reflects the size of the animal – the lower the pitch, the bigger the animal and therefore the more desirable they are to females. The frequency of the grunts also plays a role, because this represents the costly side of the signal. For an honest signal to be reliable it must be costly to send and must be of some genetic quality – otherwise the system would fall apart. If a male deer is spending more time grunting, it means it has less time available to do other things, such as eat and rest. Once males have established their harem, they will have lost a lot of weight because he hasn’t been able to eat and look after himself properly, due to spending all of his time grunting to attract a mate!
We were lucky enough to hear the male grunts! I did manage to get a video of it, but I’m not sure it’s very clear because of the wind (you’ll probably need to turn your volume right up).
Pretty cool huh! It really is an amazing (and quite hilarious) thing to witness so I’d highly recommend going to have a look for some grunting male deer if you can!
That brings us to the end of this week’s blog! I hope you’ve enjoyed reading about my lovely day at Lyme Park. Here’s a picture of some fallow deer to finish – although perhaps not quite as impressive, but still very beautiful.
See you next time!