Rooster-style combs likely helped duck-billed dinosaurs win mates

What got female duck-billed dinosaurs in the mood to make baby dinos? Perhaps it was something never before seen in the fossil record: a sexually suggestive fleshy comb, like that of roosters, on the head and neck of males.

A mummified specimen of the duckbill Edmontosaurus regalis, discovered by an international team in the west-central region of Canada’s Alberta province, proudly preserves just such a structure. The team, which reported the find online last week in Current Biology, points out that some duckbills had bony crests on their heads, which are easily preserved in fossil form, and that researchers had suggested functions for such crests ranging from sexual display to external olfactory organs. But E. regalis, a so-called flat-headed duckbill, does not have a hard, bony crest, making this first discovery of a soft tissue version all the more important for understanding dinosaur behavior.

Because birds evolved from dinosaurs, and the combs of roosters and other birds are widely considered to be for sexual display, the team concludes that this is also the most likely explanation for its presence in some duckbills.

Climate warming will stifle some bats’ ability to locate, track prey

As the planet warms, some bats will find it harder to locate and track their airborne prey, a new study suggests. The distance that sound travels before it becomes too weak to hear depends on a number of factors, including its frequency and the temperature and humidity of the air: In general, higher frequencies are more quickly stifled in warmer air.

Researchers estimate that if air temperature rises 4°C, the volume of space in which tropical bats can effectively find and track prey may decrease as much as 10 percent. For echolocating bats living in temperate ecosystems, prey detection volume might shrink as much as 21 percent, the researchers reported online last week in the Journal of the Royal Society Interface. To compensate for these losses, bats could either chirp louder, chirp at a lower frequency, or forage for longer periods each day, changes in behavior that would likely impose substantial costs.

But temperature isn’t the only climatic factor affecting the attenuation of sound, the researchers note. A complex interaction of call frequency, temperature and humidity determines how far the sound waves travel before they’re squelched. So while many bats will find life more difficult in a warmer world, some will find they can locate and home in on prey across a larger volume of space. With some of the winged predators being winners in the climate change lottery and others ending up losers, the balance of bat species in some ecosystems could shift significantly.

DNA sequencing of birds’ food may help limit airline bird strike

Bird strike costs the airline industry about $1 billion per year, and engineers have tried to reduce it using everything from loudspeakers and flares to dogs and lasers. Now, DNA sequencing has been added to the arsenal. The DNA sequences of insects and seeds – and for large predatory birds, prey such as small mammals or lizards – reveal the food that attracts the birds to the airport in the first place. 

– Adapted from ScienceNOW, an online news service of the journal Science