Evolution is simply remarkable. The sheer number of tactics employed by animals to successfully pass on their genes is astounding. So I thought I’d have a little fun today mentioning some of the strange and interesting strategies animals employ to get it on. What makes them even more astounding is that these tactics have evolved through sexual selection to produce the fittest individuals, readily equipped to pass on their genes. So remember, even though they appear strange, they have evolved for a reason.
So here you go – the weird and wonderful world of animal sex…
Anglerfish: Be a part of me
The Anglerfish is a boney fish that lives deep in the bottom of the ocean. Originally, scientists were perplexed because they had only ever caught the female of the species. Where were all the males? Adding to the mystery- all females had a growth somewhere on their bodies that appeared to be a parasite. But further investigation revealed this was in fact the male fish, reduced to a lump of sperm resources!
It turns out the males are born tiny and without a digestive system, so after they hatch they have to find a female as quickly as possible. If they do, they then bite her and begin releasing enzymes to digest some of her flesh. His body then slowly reduces into a small lump, which periodically releases sperm to fertilize her eggs.
Antechinus: Too much sex can kill you
Yes, that’s right. There is an animal out there that dies from having too much sex. The antechinus (or marsupial mouse) has such an intense breeding season that all the males die afterwards. This is mainly due to lack of food, rest and the high levels of testosterone that are sustained throughout the breeding season. After they fertilize all the females, the males of the species die off, to be replaced by their offspring next year. Just a warning, gentleman – make sure you take a break.
Leopard slugs: Just plain weird
Now take a look at this video.
Yep, not much to say on this one (Sir David said it all much better than I ever could). Leopard slugs are hermaphrodites. To mate they hang from a tree by a string of mucus, invert their glowing blue penises from just behind their heads, entwine their bodies and inseminate each other.
Seriously evolution, what are you on?
Birds: Is romance dead?
I wanted to do at least one post on birds, because from a human point of view they are the most romantic and flirtatious of all the animal groups. Check out some of these videos of bowerbirds, swans and birds of paradise – I wish I got something like that for Valentine’s Day!
But perhaps the romance of birds isn’t really all it’s cracked up to be. Recently scientists have discovered that of the species of birds that are socially monogamous, more than 3/4 have been found to be unfaithful to some degree. Although this may be devastating for some romantics, it makes sense in evolutionary terms. The females can produce offspring with a greater range of traits from different males but still have a single ‘father’ to help raise the chicks. Extra-pair copulations also, of course, allow males to spread their sperm around and produce more offspring.
For more information check out this paper from Griffith published in 2002.
Wallabies: Why have just one?
So here’s an interesting one for you – a female wallaby has three vaginas in total: two are the lateral vaginas, which lead to two separate uteri. The third is the median vagina, which is the birth canal and is not used copulation. This anatomy is also seen in a range of other marsupials.
So how do the males keep up with this? Simple – they have a two-pronged penis. I know what you’re thinking: well done evolution, with a two-pronged penis they can inseminate the female in both lateral vaginas at once. And this is indeed what scientists assumed when they first came across this odd reproductive system. However, this may not be the case – it seems that perhaps only one penis can be erect at one time, so we are still unsure of the purpose. Stay tuned!
So there you have it, a quick look into the weird and wonderful world of animal sex… and believe me when I say there is a lot more where that came from!