male
dr. dolittle | July 19, 2017 Samples of fish species from the Poeciliidae family show the diversity in color, fin size and body shape. Kansas State University researchers studied 112 species of these live-bearing fishes and found that males and females evolve differently. Image courtesy of Kansas State University
Dr. Michael Tobler and Dr. Zach Culumber at Kansas State University examined 112 species of live-bearing fish (Poeciliidae) and have made some interesting discoveries about their evolution. Their analyses included information on body shape, fin size, where the species are found and information on global…
dr. dolittle | January 22, 2015 Photo of a red-eared slider turtle by Nightryder84.
Dr. Thane Wibbels (University of Alabama at Birmingham) is interested in studying how temperature affects the sex of red-eared slider turtle embryos. For humans, the answer is simple: sex chromosomes. You know, the combination of XX means girl and XY means boy.
Turtles are not that simple. Temperature is a factor in determining whether the embryo will be male or female. If the eggs are incubated at 78.8 degrees F, the hatchlings will all be male. If they are incubated at 87.8 degrees, they will all be female. As I'm sure you've guessed,…
dr. dolittle | October 26, 2014A recent study published in the American Journal of Physiology - Regulatory, Integrative and Comparative Physiology presents evidence that altering the sex of just the fat body in heads of fruit flies (Drosophila) causes them to have stress responses similar to the opposite sex.
Males and females vary in their response to stress. It turns out that this difference is not unique to mammals as male and female fruit flies also show similar variations. In fruit flies this is thought to be due to differences in the neuronal circuits between the sexes, which may also explain some of the variability…
edyong | March 17, 2010For most men, the thought of taking on the burden of pregnancy from their partners would seem like a nightmare, but it's all part and parcel of seahorse life. After mating, female seahorses and pipefish lay their eggs into a special pouch in the male's belly and he carries the developing babies to term. They may seem like a shoe-in for a Dad-of-the-year award but this apparent display of paternal perfection has several macabre twists.
A recent study showed that pregnant pipefishes can also become vampiric cannibals, absorbing some of their brood for nutrition if their own food supplies are…
edyong | March 10, 2010The animal on the right is no ordinary chicken. Its right half looks like a hen but its left half (with a larger wattle, bigger breast, whiter colour and leg spur) is that of a cockerel. The bird is a 'gynandromorph', a rare sexual chimera. Thanks to three of these oddities, Debiao Zhao and Derek McBride from the University of Edinburgh have discovered a truly amazing secret about these most familiar of birds - every single cell in a chicken's body is either male or female. Each one has its own sexual identity. It seems that becoming male or female is a very different process for birds than…
sastyk | February 4, 2010As you all know, I live with five males, ranging from 39 to 4. As a woman raised in a mostly all-female household (mother, step-mother, two sisters), I try gamely to fit in, but find myself occasionally mystified by the guy-ness, or inadequately equipped for things like appreciating how cool it is to write in the snow with your penis. This was clearly one of those moments.
Me, (coming downstairs for a cup of tea before returning to my book) "What's with the sledgehammer, honey?"
The boys: "Daddy is going to let us smash geodes! Awesome! We tried it with the hammer, but it didn't work, so…