Several recent studies have drawn a link between sex, climate change and environmental pollution. Here's a round-up of these and a few more.
Polar bear penis bones are shrinking in Eastern Greenland, according to Christian Sonne of the University of Aarhus in Denmark and colleagues. They found that polar bears living in the Eastern Greenland are somewhat less well endowed than their cousins in Svalbard and the Canadian Arctic. They say this could be due to the high prevalence of pollutants such as PCBs and DDT in Eastern Greenland - pollutants which records show are less prevalent in Svalbard and the Canadian Arctic.
In 2004, Steven Fergusson of the University of Manitoba in Canada showed that carnivores living in snowy environments, close to the poles, tend to have longer penis bones to help them be more competitive.
So Sonne's group concludes that human pollution, combined with the difficulty of finding food in warming climates, may spell disaster for Eastern Greenland polar bears.
Male birds rule the roost
By and large there are one third more male birds out there than females, according to a new study by Paul Donald of the UK Royal Society for the Protection of Birds. This is despite the fact that as many hatchlings of each sex born. So the researchers conclude that unlike humans, female birds must have shorter life expectancies than males.
The finding is bad news for conservation efforts, which often estimate the size of populations by counting the number of males - it seems threatened birds might be even more thin on the ground than previously thought. Strikingly, the researchers also found that the sex ratio was even greater in threatened species.
Turtles go the distance
Female loggerhead turtles in Florida, US, increasingly rely on long-distance relationships with males in North Carolina, according to research our of the University of Exeter in the UK. That's because the sex of the loggerhead hatchlings is determined by the temperature at which the egg is incubated: warmer temperatures yield females, cooler ones yield males. So warming temperatures in the US mean that southern populations of loggerheads are increasingly dominated by females.
Bearded dragon sex switched by heat
Similarly, the sex Australian central bearded dragons can be "switched" by heat. A team of researchers led by Alex Quinn at Canberra University in Australia recently incubated eggs at relatively high temperatures – between 34°C and 37°C and found that the majority of embryos that had ZZ sex chromosomes (genetically male), went on to hatch as females. The team is worried that the lizards may not be able to adapt fast enough to warming temperatures, leading to males being wiped-out altogether.
Penguins and post-El Niño stress disorder
It seems that Galápagos penguin may suffer from post-El Niño stress disorder. After the strong El Niño events of 1982–83 and 1997–98 populations declined by more than 60%., according to F. Hernán Vargas of the University of Oxford and colleagues. They also looked at what this means for the future of the species and found a 30% chance it will disappear entirely within 100 years, if El Niño events keep happening with the same frequency. If, however, the frequency increases, as predicted by some climatologists, the risk becomes greater. A doubling of the strong events leads to an 80% of extinction within 100 years.