Polar bears are evolutionarily older and genetically more distinct than believed. This largest Arctic carnivore evolved as early as 600,000 years ago, five times older than previously recognized. 

Why do our closest primate cousins spend more time suckling their young than we typically spend nursing ours? This question has been heavily debated over the past several decades, but to date there is more information on the implications of our relatively short lactation periods than on their causes. One reason it has been difficult to address this question empirically is that there is not much variation in large-brained primates in some of the traits that are hypothesized to impact suckling behaviors; thus, it is difficult to explore how these characteristics could affect lactation and parenting.

Climate change is in its fifth decade of being the big concern. In the 1960s and 70s, it was a cooling worry but now there is a warming one.  A constant in mammal's surviving numerous climate upheavals throughout earth history has been diversity - the relative range and distribution of mammalian families remained strikingly consistent throughout major climate changes over the past 56 million years.

Why aren’t there are super pygmy vertebrates?

For most vertebrate animals, their early embryonic development unfolds in extremely congruent fashions.

Embryo growth is stem cell-dependent and in large part, despite different gestational periods, the molecular and cellular machinery that controls vertebrate development is almost perfectly conserved.

Some microorganisms lose the ability to perform a function that appears to be necessary for their survival, and yet they still somehow manage to endure and multiply. How can that be? 

One hypothesis says microbes that shed necessary functions are getting others to 'do that work' for them, an adaptation that can encourage microorganisms to live in cooperative communities. Yes, genetic inter-organism cooperation and adaptive gene loss.

Lucy, Australopithecus afarensis, was not walking around Africa alone three million years ago.  

Biologists knew that, of course, the neatly linear line from critter to modern man does not exist, it happened in fits and starts and sometimes different ways numerous times. But as the study of evolution becomes more multi-discplinary our chances of finding new fossils increases, and ideas of what ancestors looked like go from theoretical to real.

Are you ugly?  Maybe that's something else to blame your mother about.

Female cognitive ability can impact how handsome males become over evolutionary time, say biologists from The University of Texas at Austin, Louisiana State University Health Sciences Center and the Smithsonian Tropical Research Institute. Males across the animal world have evolved elaborate traits to attract females, from huge peacock tails to complex bird songs and frog calls. But there is a price - predators are attracted to increased elaboration, placing an enormous cost to males with these sexy traits. In a new paper, a group of biologists have shown that females can also limit the evolution of increased elaboration.

Researchers have completed the genome sequence for the gorilla, the last genus of the living great apes to have its genome decoded. The results confirm that our closest relative is the chimpanzee but much of the human genome more closely resembles the gorilla than it does the chimpanzee genome.

For the first time, scientists can compare the genomes of all four living great apes: humans, chimpanzees, gorillas and orangutans. This provides a unique perspective on our own origins and is an important resource for research into human evolution and biology, as well as for gorilla biology and conservation.  

A new paper in Nature details how prions might generate heritable phenotypic diversity. In general, the heritable variation that underlies evolution is thought to find its root in mutations affecting the genetic code. In recent years, however, other potential mechanisms have been investigated, collectively known as epigenetics. This means that, even without changing the genetic code itself, heritable variation might be generated. The two most well-known mechanisms that achieve this are DNA methylation and chromatin remodeling.