Welcome to our first UWOL newsletter. Under Water, Over Land will be bi-monthly peek into the lives and activities of our aquatic and terrestrial friends from around the world. We will try and provide you with some interesting facts, fun, and a bit of humour, for you to slip into conversation on the dive boat on the way to a dive site, sitting round the camp fire in the evening, or down the pub. We will also look at conservation initiatives, with the  focus being on positive results rather than beating a negative drum.

For our first issue, we thought we’d take a light-hearted look at some of the odder sexual practices that go on underwater and on land.

1. Sex-changing clownfish

All anemonefish are born male and the largest adult male services a larger, dominant female, whilst the non-breeding males live on the same anemone. Unfortunately for the alpha male, when his partner dies he changes sex and replaces her as the object of one of his friends’ desire. Potato grouper do it the other way round, females turning into males when required and growing to two metres and 200 kgs.

2. Argonauts and their detachable swimming penises

An argonaut or paper nautilus is a species of octopus. First, they have highly divergent sexual dimorphism. That’s geek-speak for the difference in body sizes and shapes between males and females. A female argonaut grows up to 10 centimetres with a shell as large as 45 cm. The small male, however, is only two centimetres long. Odd-sized couples are not that odd, but what is very freaky is the male argonaut producing a ball of spermatozoa in a special tentacle called a hectocotylus. When meeting a female it fancies, the male then detaches its penis that swims off by itself to fertilise the female all on its own.

3. Cross-dressing cuttlefish

Cuttlefish mating season is no place for the meek. On average four, but up to eleven, males compete for the right to fertilise one female. It’s a good place to be a big guy. Yet one-third of all matings are carried out by little blokes. How do they do it? Well it’s a matter of brains over brawn. Either the mini-male waits until the big guys are busy fighting and nips in to get his leg, or rather tentacle over, or more commonly he uses the cuttlefish’s natural skills of camouflage and mimicry to impersonate a female and sidle up to his intended mate without incurring the wrath of the dominant males around under the cloak of his girly disguise.

4. Inflatable Barnacle Penises

Barnacles, those molluscs that stick themselves to the bottom of boats and rocks, are stuck in one position all their lives. That could make reproduction a sticky issue, but they have an inflatable penis up to eight times their body length, the biggest penis-length-to-body-size ratio in the animal kingdom. If humans had the same we could mate from 14 metres away.

Barnacles regrow their penises each year, just before their brief mating season, and research has shown that water conditions play a key role in organ shaping. In calm waters, barnacles grow long, flexible penises in order to reach as many mates as possible. However, in rougher waters, they develop more muscular, stubbier penises for more control.

5. Nudibranch hermaphrodite sex parties

Fantastically coloured nudibranchs are part of the 800+ species-strong sea slug family. As hermaphrodites they have both male and female reproductive bits and when they find a partner they fertilise each other simultaneously through the same organ. Some species called sea hares have the male organ on the side of their head and the female organ on their underside and form long chains in an aquatic mollusc orgy. The front and rear ones missing out on half the fun, as they only play one sexual role.

6. Penis jousting – loser takes all

Another member of the sea slug family, the flatworm, are also hermaphrodites  and have a two-headed dagger-like penis. Mating is a violent rumble where two combatant lovers try to pierce each other with one of their spiky white appendages. The "winner" is the one that stabs and inseminates the other first  as it becomes the father. The “loser” assumes the role of the mother and as such has to expend considerable energy producing and caring for the developing eggs whilst the victor ambles off to find another duel.

7.  Dolphins' prehensile swivelling penises

Here’s something you probably don’t know about Flipper: he has a retractable penis that is prehensile like the tip of an elephant’s trunk. And it swivels. In fact, a male dolphin can use his penis to explore objects just like a hand. Male dolphins also have a high very libido and try to mate with inanimate objects and even other animals like sea turtles. They can mate many, many times in a day although the average time to ejaculation is only 12 seconds.

8. Octopus one shot wonders

One night stands  will be with us forever. The same is true for the male octopus, yet he will never have the next-day pangs of regret. Alas for the poor male octopus he only gets one ride on the big wheel. Once he has found a mate, he insets packets of sperm using a special tentacle into her mantle. In the process he loses the appendage and ultimately his life, as mating is a one-off experience in most of the 300 species, and death follows shortly after.

9. Anglerfish antics – freeloading fellas

Anglerfish, a deep sea fish named for the rod-like appendage on its head that it uses as bait to attract prey, spend their time in the dark depths of the ocean, and finding a mate is a problem – but the species has solved this evolutionary challenge beautifully.

Having never caught a male anglerfish scientists were puzzled until they looked very closely at a parasite-type lump found on female bodies that was the remains of the male fish. The tiny males are born without any digestive system, so once they hatch they have to quickly sniff out a female by detecting the pheromones she releases. Biting her body he secretes an enzyme that digests both his skin and her body, fusing the two together in an eternal embrace. The male then wastes away, becoming nothing but a sack of sperm on the female anglerfish’s body. One rather attractive female was found with 12 paramours stuck to her side.

10. Giraffe fertility tests

You'd have thought that an animal that can have a head six metres off the ground would have figured out a comfortable way of finding a mate using its height. Think again. As mounting a female giraffe and mating is rather hard, males want to know that it’s going to be worth the effort. To see if she is in oestrus he carries out a thing called the flehmen test. Bending his head down he nudges her backside to induce urination which he then samples. If he likes what he tastes he runs after her and mounts her before strolling off to find his next conquest.

 The lack of tenderness is no cause of grief for the female as giraffes use a system of overlap promiscuity, meaning that individuals mate haphazardly with others within their home ranges. There is no prolonged relationship and males do not defend or care for young.

11.  Bonobo Monkeys – make love not war.

Who said that violence is the only way to solve fights over food or territory? Instead of fighting, bonobos have sex! Actually, their whole societal structure seems to revolve around sex. Bonobos use sex to greet, solve disputes, make up after fights, and as favours in exchange for food. They tongue kiss, indulge in oral sex and mutual masturbation, have face-to-face sex and even have a "penis fencing" ritual. Chimpanzees and Bonobos both evolved from the same ancestor as humans, and yet the Bonobo is one of the most peaceful, unaggressive species of mammals living on the earth today. They have evolved ways to reduce violence that permeate their entire society. The evolutionary dance of violence is not inexorable (as long as you swing from the trees naked).

12. Munching Mantis  - Fatal attraction

Pity the male praying mantis. In the wild he has a 30% chance of getting his head bitten by his partner during sex. The praying mantis brain, located in the head, controls inhibition, whilst a ganglion in the abdomen controls the old Elvis pelvic hip thrusts. Therefore when a male loses his head he also loses all his inhibitions and mates with wild abandon. It is also believed that the protein-rich brain provides a food source, thus ensuring fertilisation is not wasted. It has also been theorized that fear of being eaten makes males go about sex as heartily as possible to successfully satiate and satisfy the female meaning that she feels no need to remove his inhibitions.

13. Fruit Flies – size does matter

The title of world’s longest sperm belongs to a tiny fruit fly called Drosophila bifurca. When the coiled sperm is straightened out, it measures almost six centimetres long which is over 1,000 times longer than a human sperm. In fact, a male fruit fly’s testicles make up 11 percent of its body weight, equivalent to nine kilos in an 80 kg man .

Scientists have discovered that females of most species of fruit fly, are promiscuous and have a specialised storage organ where sperm from different males compete in the race to fertilise an egg. They found that the bigger the female’s storage device, the greater the advantage of males with longer sperm.

14. Spider digital ID

There are 40,000 species of spider. Ever wonder how they didn’t crossbreed to produce? Rather than have a penis like most males, male spiders use their palps, a sort of hand and arm arrangement with a boxing-glove shaped end specific to its species. Loading them with a sperm web, the male performs a long and arduous routine to convince the larger female to receive his gift. If he gets it wrong then she eats him. That's a pretty harsh sanction for getting your moonwalk wrong. The female epigyne will only accept palps from her species, like a key fitting into a lock.