Monday, 28 May 2007

Men, can live with them, can live without them

Sex is not necessary for all members of the animal kingdom. Of course it has its advantages, primarily, combining genetic material adds to the diversity of a species and makes it more ‘hardy’. But in vertebrates, organisms that are considered ‘more complex’ (ie. fish, amphibians, reptiles, birds and mammals) asexual reproductions is extremely rare and is thought to be limited because of the complexity of vertebrate genetics and body plans.

Recent discoveries has defied this logic however. A captive female hammerhead shark had a ‘virgin’ birth. The shark, which lives at Henry Doorly Zoo in Nebraska gave birth to a pup despite having had no contact with a male. A similar incidence was reported of a komodo dragon in Chester Zoo in the UK.

Originally it was thought that the females were storing sperm from a previous encounter for an extended length of time but genetic tests have now confirmed that the offspring share their DNA with only individual, their mother. This type of reproduction is known as parthenogenesis and it not entirely clear how or why it developed. One theory suggests that it evolved as a mechanism to deal with times of isolation. For example, if a komodo dragon found itself on an island without a mate, a few offspring could be produced while it waited for another komodo dragon to arrive and the population could be sustained until a viable breeding pool arrived.

This new ‘twist’ has created many questions including what other animals are capable of reproducing in this fashion. So far the ability has not been documented in mammals and birds but it has only been with the recent advent of genetic testing that such unusual cases can be investigated.

Friday, 25 May 2007

Only in America....

Ok this is off topic but I found this article too funny not to mention.

Only in America can I guy openly surf for pornography at his workplace, be warned against the behaviour and then, when he is fired, turn around and sue the company for $5 million USD for wrongful dismissal. Apparently he is arguing that he was 'self-medicating' for his sex addiction.

No matter what you say, I still think humans have the oddest sexual behaviour:)

Lovesick albatross still looking for romance after 40 years

Albert, a lovesick albatross was blown off course 40 years ago and has been living in Scotland since 1967. Over the last four decades he has been wooing gannets, in his desperate search for a mate. But being 8,000 miles away from his natural breeding ground, he has been unsuccessful in finding a suitable partner. Albert’s natural home is in Southern Argentina and the Falkland Islands. Read more about Albert at the BBC website.

Thursday, 24 May 2007

Gay flamingos pick up chick

Carlos and Fernando, a pair of gay flamingos have adopted an abandoned chick. Zoo staff say they have been desperate to start a family, even chasing other flamingos from their nests to steal their eggs at the Wildfowl and Wetlands Trust (WWT) in Slimbridge near Bristol.

And so they were chosen as adoptive parents for an unhatched egg when a nest was abandoned. The males have the ability to feed chicks by producing milk in their throats.

The couple has been together for six years and WWT spokeswoman, Jane Waghorn, says "Gay flamingos are not uncommon. If there aren't enough females or they don't hit it off with them, they will pair off with other males."

Wednesday, 23 May 2007

Ever wondered how dinosaurs… er…you know…did it?

Check out this discussion between expert biologists and palaeontologists at the Ask a Biologist website about the latest theories on dinosaur sex, from balancing sauropods to spiny stegosaurs.

Tuesday, 22 May 2007

Bats: More brain than brawn?

Brains or brawn, which is more important? Can you have both? Well not if you’re a male bat. A recent study has shown a negative correlation between brain size and testicle size in bats; so for bats, intelligence comes at a steep price.

One theory is that the development of a large brain or large testicles is ‘expensive’ so bats can’t afford both.

Scott Pitnick, of the Syracuse University in New York conducted the research and says "The male who ejaculates the greatest number of sperm may win at this game, and hence many bats have evolved outrageously big testes. Because they live on an energetic knife-edge, bats may not be able to evolutionarily afford both big testes and big brains."

Females bats of many species mate with more than just one male and can store their sperm, leading to fierce competition. Pitnick believes that there is an important link between fertility and testicle size. After analysying 334 species of bats, Pitnick’s team found that in species with promiscuous females, males had evolved larger testicles and had relatively small brains. In species where the females were faithful to their mates, the correlation was reversed. Interestingly, male fidelity appeared to have no link to testicle or brain size.

In some bat species, the males' testicles can be as much as 8.5% percent of its body mass. In contrast, primates' testicles (including humans) is less than 1% of body mass.

Thursday, 17 May 2007

Lonesome George still a devout bachelor

Lonesome George, a giant Galapagos tortoise and mascot for conservation is the last of his kind. George has long chosen been a dedicated bachelor, even when given his chosen of female mates from a closely related species. Hopes rose last week when a hybrid tortoise was found last week, but unfortunately this animal is also male, so it has not changed the fact that George is unlikely to settle down and start a family anytime soon.

Wednesday, 16 May 2007

Courtship displays at the Attwater Prairie Chicken Festival

This yearly festival is an opportunity for people to witness the unusual mating habits of the Attwater Prairie Chicken, an endangered species in Texas. For those that couldn’t attend, you can check out a description of their colourful mating behaviour at the Victoria Advocate’s website.

Tuesday, 15 May 2007

Cooperative Mating Behaviour in Sharks

Looking through some of Brian Larnder’s past post of Sexiest Animal on the Planet, I discovered this interesting article on sharks. I was surprised to learn about the advantages of male sharks engaging in teamwork to inseminate a female!

Monday, 14 May 2007

Terrifying Turtle Organs

Check out Darren Naish’s posting on Terrifying Sex Organs of Male Turtles. I believe this post coins a new phrase, “Hung like a turtle”.

This week's column...

will be postponed until Friday. Sorry life has been a bit crazy as of late. In the mean time, enjoy related topics explored around the web.

Friday, 11 May 2007

Panda Mating Frenzy

Last week’s column on Panda Pornography focused on the difficulties of mating pandas in captivity. This week, read about a successful matchmaking in BBC’s article about a Panda Mating Frenzy Hitting San Diego Zoo.

Thursday, 10 May 2007

Sexy Sponges

Check out this week’s Sexiest Animal on the Planet: Sponges over at the Primodial Blog. As Brian Larnder says, you’ll never look at a sponge the same way again.

Wednesday, 9 May 2007

Bedbugs Shoot Up Too

In follow up to Monday's post on Giant Squids Shooting Up, the behaviour of ‘injecting’ sperm directly into the female is not limited to the giants of the seas. A male bedbug of the genus Cimex uses a spike on his penis to pierce a hole through the female's back. He then ejaculates into this hole and his sperm swim around the female's blood until they reach her ovaries. The fertilized eggs then develop into embryos which are born alive in the usual manner. How and why such a system developed is a mystery.

Tuesday, 8 May 2007

Kinky Ducks

Check out Carl Zimmer’s column on Kinky Duck Sex. The males have absurdly long phalluses and the females have convoluted, spiral shaped organs.

Monday, 7 May 2007

Giant Squids Shoot Up

Living in harsh environments such as hot deserts, deep seas and high mountains means that potential mates are few and far between so when you encounter another member of your species, you have to grab the opportunity. The Giant Squid (Architeuthis) is one such animal. It lives in dark deep depths 1000m below the ocean surface. These tentacled creatures meet rarely and are even more rarely observed by humans.

These giants beasts can reach lengths of 15m (45ft) and the male delivers his load by means of a 1m (3ft) long muscular, prehensile penis. But instead of making the delivery in a conventional fashion, he actually stabs the female with his appendage and deposits sperm into the wound. A female giant squid captured off of Australia’s southern coast had sperm embedded in her arms.

This allows the female to store the sperm for long periods, a useful option since encounters with males are infrequent at these great depths. It is not clear how the female uses the sperm when she is ready to fertilize her eggs. Perhaps she reopens the wound to retrieve the souvenir he left behind or maybe hormonal cues cause sperm migrates to the surface.

A male giant squid caught off Norway in the 1950s also had sperm embedded in his skin. This seems odd but when you are a lonely animal living in a vast, empty world you have take action when a the opportunity presents itself. Shoot first, ask questions later.

Tuesday, 1 May 2007

Voyeuristic Sea Lions and Panda Pornography

Pornography is a human invention but there are animals who are not adverse to a little voyeurism: California sea lions are an example. They are stimulated by the sight of other sea lions having sex and given the opportunity will engage in the act after watching it.

Older males have a ‘harem’ of females who can be quite demanding. The Old Man is expected to satisfy all of their sexual needs, one at a time. They copulate for about an hour, floating just below the surface of the water and once they are done, the male hurries ashore for his next date.

Younger males watch the alpha males copulate with their females but usually can’t participate, as the older males jealously guard their females. So for the younger male, voyeurism is his only way of receiving sexual satisfaction.

Indeed, it is thought that for many vertebrate animals voyerism is ‘instructional’, especially for the males. But if animals such as these are raised in captivity, without the benefit of instruction from elders, how far will their instincts take them?

In some cases not far enough. Breeding pandas in captivity has been historically difficult, so in recent years some conservationists have taken novel measures to help the animals along.

In Thailand's Chiang Mai Zoo, two pandas, Chuang Chuang and Lin Hui, resided quite happily (and abstinately) for four years.The pair were sent from China in the hope that the comfortable climate at the Thai zoo would be enough to set off a few sparks between the two. Zoo officials waited anxiously for the pair to warm up to each other and start a family. Finally, a first faltering, attempt was made by the couple but unfortunatly, it failed to produce offspring. The pandas, apparently having satisfied their curiousity, remained ‘friends’ and did not stike up a romantic relationship again.

Zookeepers decided that the platonic relationship needed a bit of help so they formulated a unique plan: Chuang Chuang, the six-year-old male, viewed films of other mating pandas when researchers thought he was most relaxed and receptive.

Unfortunately, panda porn didn’t work for Chuang Chuang who seems to want to keep his relationship with Lin Hui strictly platonic. And Lin Hui seemed to be daunted by the prospect since Chuang Chuang has gained some love handles. So zookeepers put Chuang Chuang on a strict diet, hoping that his new physique would turn Lin Hui’s head, but to no avail. Last month, scientists resorted to artificial insemination.

The end result? The pornography wasn’t a success, perhaps they're just not each other’s type. But maybe the miracles of modern technology will help the quest for a baby. Only time will tell.

More information:
Chiang Mai Zoo
National Geographic News

Welcome to the Secret Sex Lives of Animals

Birds do it. Bees do it. Humans do it. In fact every animal on this earth does it. But do they all do it the same way? Mating habits in the animal kingdom range from the sublime to ridiculous, but each animal, in their own unique way, accomplishes the same goal.

Welcome to the Secret Sex Lives of Animals, a weekly column on the bizarre, wonderful, colourful and sometimes shocking world of animal mating habits.

Why does a praying mantis kill her mate, sometimes before they even finish the act?
Is there an evolutionary advantage of having three sexes instead of two?
Why are dolphins so promiscuous and beavers so monogamous?

The Secret Sex Lives of Animals is published each Monday at 12:00 pm GMT.