In general, human beings tend to be quite generous. As such, it is not a big step to question whether the same is true for our close evolutionary cousins, the chimpanzees (Pan troglodytes). A new study indicates that it might.

When it comes to chimp sharing behavior, there has long been a discrepancy between studies in the field, and those in laboratory settings. In the field, chimpanzees have been known to share food, console each other and lend support during a fight. In lab experiments, however, chimps don’t really share, and are viewed as ‘reluctant altruists’, sharing only when prompted by solicitation and other forms of pressure.

Anisogamy (see figure 1), or sexual reproduction in which two different gametes fuse to produce a new individual, leads to an inequality between female and male organisms. After all, females produce a limited supply of costly egg cells, while males produce a virtually endless supply of cheap sperm cells (this is the case in the vast majority of animals, and is known as oogamy (see figure 1), in which a large, non-motile egg cell is fertilized by a small, motile sperm cell (see figure 2)) . So, females best carefully choose the male they mate with, while males best copulate as much as possible, with as many females as possible. Females are choosy, males are promiscuous. Of course, there are exceptions, but still, this holds true in many cases.

Creating sperm or egg cells in the laboratory has been tried several times in the past few years. The reasons for this range from a better understanding of the fundamentals of the reproductive process, to helping infertile couples with their child-wish. The attempts, using embryonic stem cells, however, did not yield viable germ cells.

Until now.

A research team at Kyoto University has succeeded in turning mouse embryonic stem cells into viable sperm precursor cells. The resulting sperm cells was subsequently used to give birth to healthy, normal cute little mice (see figure 1).

Imagine going through customs with everything in order. Passport’s okay, and all seems fine. But when your fingerprints are scanned, the customs agents are looking surprised. Apparently, you have no fingerprints. Sounds weird, right? And yet, it is exactly what happened to a Swiss woman in 2007 when she tried to enter the United States.

As it turned out, the woman had a very rare condition known as adermatoglyphia, leading to a lack of fingerprints (see figure 1), and a lower production of hand sweat than the average person. Very little is known about the condition, and so far, only four families carrying the mutation have ever been documented.

Most of us don’t have a problem attributing emotions to primates, dogs, horses and other vertebrates. But what about invertebrates? That seems less obvious. They have smaller, less complex brains, but is that enough to boldly claim they have no emotions? Of course, studying animal emotions is a precarious business. Studying human emotions has already proven difficult enough, and in animals it is bound to be a lot harder.

One way to go about it, is to take a look at so-called cognitive biases, biases in the processing of information that are typical of negative affective states. An example of this is the pessimistic bias, an increased expectation of punishment, greater attention to potential threats and a tendency to interpret ambiguous stimuli as if they were threats.