If you've ever complained about having bad sex, you really have no idea. Human women may have to complain about poor stamina or incompetent technique but the female seed beetle (or bean weevil; Callosobruchus maculatus) has to contend with her partner's nightmarish penis - an organ covered in hard, sharp spikes. Just see if you can look at the picture on the right without wincing.

It's no surprise then that females sustain heavy injuries during sex. But why have male beetles evolved such hellish genitals? What benefits do they gain by physically harming their partners?

It's possible that the injuries directly benefit the males, either because they stop the females from mating again or spend more efforts in raising their fertilised eggs to avoid the strain of future liaisons...

The courtship rituals of the spider Harpactea sadistica start innocently enough, with a dance and a hug. The male spider taps the female gently with his front legs and embraces her. But from that point onwards, things for the female go rapidly downhill. The male bites her and she becomes passive, allowing him to manoeuvre her into position. Like all spiders, his genitals are found next to his head, on a pair of appendages called the pedipalps. But unusually, his penis ends in a needle-sharp tip called an embolus.

The embolus sits at the end of a loop called the conductor. The male hooks one of these loops around the opposite embolus to steady it. Then, by rotating the anchored needle, he drives the point straight through the female's underside and ejaculates directly into her body cavity. On average, he does this six times, moving slowly downwards and alternating between his two penises. The entire cringeworthy sequence lasts about 15 minutes and throughout it, the male spider never penetrates the female's actual genital opening...

Dogs, cats, lions, bears, and a number of other mammals self-stimulate with their front paws; randy walruses use their flippers. Horses and donkeys, whose masturbatory habits have been particularly well-studied, engage in "rhythmic bouncing, pressing, or sliding of the erect penis against the abdomen"; male deer do the same. The 19th-century physiologist Karl Friedrich Burdach has even described something like female ejaculation among solitary mares, which "rub themselves against whatever obstacles they find, often spurting a white, viscous mucus." A bull, meanwhile, stimulates itself by alternately protruding its penis from a genital sheath, while some moose can ejaculate simply by rubbing their antlers on bits of vegetation. According to observations made at the University of Buffalo in the 1940s, both male and female porcupines manipulate their genitals with inanimate objects—they're also known to "seize, straddle, and ride sticks about the cage."...

The End of the Line is a powerful film about one of the world's most disturbing problems - over-fishing. Advances in fishing technology mean whole species of wild fish are under threat and the most important stocks we eat are predicted to be in a state of collapse by 2050. The film points the finger at those most to blame, including celebrity chefs, and shows what we can do about it. This is not just a film, it is also a campaign - for sustainable consumption of fish, for marine protected areas to allow the sea to recover, and for a new ethic of responsible fishing.

An animal park in Florida has found a unique way to develop bonds between humans and tigers. [...]

The hand-reared tigers are introduced to the water a few months after birth and the trainers then give one-on-one tuition to each of the animals while they are in the water.

"At the institute we feel that swimming with the big cats gives them a closer bond between the animal and their human companions," said Mr Antle.

But despite the apparent danger, he said his trainers are never at risk.

"We found that in the water people and tigers were on a more equal footing when the tiger was swimming around on the top.

"As they were floating around we could manipulate them more easily because they don't stand up on their back legs."

With a potential to grow to over 500 lbs and eight feet in length, it is often considered that handlers will only swim with the tigers when they are no more than a year old.

"I personally have had full grown 15 year old adult tigers that I swam with," Mr Antle said. "But that is me and I wouldn't put my staff at the same risk."

Two penguins native to Antarctica met one spring day in 1998 in a tank at the Central Park Zoo in midtown Manhattan. They perched atop stones and took turns diving in and out of the clear water below. They entwined necks, called to each other and mated. They then built a nest together to prepare for an egg. But no egg was forthcoming: Roy and Silo were both male.

Robert Gramzay, a keeper at the zoo, watched the chinstrap penguin pair roll a rock into their nest and sit on it, according to newspaper reports. Gramzay found an egg from another pair of penguins that was having difficulty hatching it and slipped it into Roy and Silo’s nest. Roy and Silo took turns warming the egg with their blubbery underbellies until, after 34 days, a female chick pecked her way into the world. Roy and Silo kept the gray, fuzzy chick warm and regurgitated food into her tiny black beak...

"Although mating has never been observed in giant squid, it is thought that what happens is that the male injects his sperm packages into the female's arms. The process is likely to be a fairly violent affair as the female is probably not that keen on being injected. This is a problem for the amorous male as females are normally a third bigger than they are.
"But males get round their inferior size by being endowed with a particularly long penis, which means they can inject the female without having to get too close to her chomping beak. The male's sexual organ is actually a bit like a high-pressure fire hose and is normally nearly as long as his body - excluding legs and head.

"But having such a big penis does have one drawback: it seems that co-ordinating eight legs, two feeding tentacles and a huge penis, whilst fending off an irate female, is a bit too much to ask, and one of the two males stranded on the Spanish coast had accidentally injected himself with sperm packages in the legs and body. And this does not seem to have been an isolated incident since two of the eight males that had stranded in the north-east Atlantic before had also accidentally inseminated themselves.