Posted on Saturday 6 November 2004

Assume for the minute that the huge meteor that slammed into the Earth at Chicxulub 65 million years ago, blackened the skies sufficiently so as to plunge the entire planet into winter and change the climate irreversibly. Perhaps the most remarkable thing about this scenario is not the well-publicised extinction of the dinosaurs but rather the survival of many other species, especially the ones that today differ very little from their Cretaceous predecessors.

Exhibit A, the humble honeybee.

Bees evolved during the Jurassic period in symbiosis with flowering plants around 125 million years ago. The bee pictured here, encased in amber for the past 80 million years, is of the species Cretotrigona prisca. This is a species that survived the Cretaceous-Tertiary extinction event and is almost identical to its modern-day cousin Dactylurina which today lives in tropical Africa.

Bees are notoriously sensitive to temperature and cannot stand very cold conditions. The mere fact of the survival of this tropical variety (which must also have relied upon the presence of flowering plants) implies a lower limit to the depth of this Chicxulub-induced winter. Drops in global temperatures of between 7 and 12 degrees celsius are often advanced, however based on what is known about the Cretaceous period and about bees in general, estimates of the severity of this dip would need to be reduced considerably, probably by more than half.

"I'm not trying to say an asteroid impact didn't happen," says researcher, Jacqueline M. Kozisek of the University of New Orleans. "I'm just trying to narrow down the effects."

Basically, the dinosaurs must have been wimps.