I have recently become fascinated with an awesome topic in biology and evolution that I feel is rarely covered in biology courses. That is, rates of meiotic recombination, or the the amount that an organism's genome is reshuffled before it is passed on to the next generation, varies across species! And no one really knows why. A recent paper by Segura et al which gathered average recombination rates for males across a dozen or so mammals and showed that there is a trend of increasing recombination rate with mammalian divergence.
Why is recombination increasing through mammalian evolution? Is there any reason to believe that there is something special about placental mammals which would drive increased recombination?
There are some catches to this study such as low sampling of marsupials and monotremes and low power for most of species wide recombination rates, ie the average recombination rate of cells in a single individual. But I can see how getting samples from multiple tigers would be difficult.