Dinosaur Courtships: Same Old Song And Dance
Predatory dinosaurs danced to woo their mates. At least, this is what is being claimed on the basis of new research conducted by an international team of paleontologists. This interesting discovery was made when the scientists studied the multiple series of scrape marks left behind by these prehistoric creatures in a 100 million year old sandstone bed in the state of Colorado in the USA. Scientists claim that this mating behavior likely seen among these gigantic animals represents the origins of the spectacular mating rituals (the lek phenomena) of their descendants: modern day birds.
What is a Lek?
The term lek is derived from the Swedish word lek, meaning "pleasurable, and less rule-bound, games". Leks are competitive displays by the males of an avian species taking place before and/or during the breeding season, carried out in order to attract female mates towards them. During a lek phenomenon, males aggregate in a common display ground where each male exhibits the best he has to offer in terms of dances, prances, feather displays, and mating calls. The ultimate aim of each male in the lek is to entice a female towards him for mating. Leks might be classical ones, where males occupy territories within visual and auditory range of other males, or "exploded" where the lek area is more expansive and males are not within the visible range of each other. The stability of leks is also quite baffling. Often, males aggregate at the same lek location in successive breeding seasons, while females revisit the same lek to mate with their previous male partner. It has often been observed that female birds do not visit a lek site if their male partner of the previous breeding season is not present in the site for the present season.
Species that Exhibit Lek Mating
Although lek mating systems primarily prevail in avian species, certain insects, amphibians, reptiles, and even mammals exhibit lek-like behaviors as well. Among birds, lekking is most common among species like the Sage grouse, Black grouse, Great bustard, Great snipe, and Prairie chicken. The lekking phenomenon of Birds-of-Paradise offers some particularly breathtaking sights. The critically endangered Kakapos living in New Zealand exhibit the exploded form of lekking behavior, wherein they position themselves several kilometers away from each other, making booming sounds to entice females. Insects like Red Harvester ants and certain bee species also exhibit lekking behaviors, wherein males congregate in a specific location and are found secreting pheromones together, prospectively attracting potential female mates to the same spots. Mammalian species exhibiting lek mating include some species of fruit bats, the Ugandan kob antelope, the Topi antelope, and some pinnipeds (a clade including sea lions, walruses, and seals). Some fish species and marine iguanas also exhibit lekking behavior.
Turning our attention back to the Mesozoic Era, it appears that the giant dinosaurs were not any less dramatic and effortless in their attempts to woo their mates than what is seen among present-day birds. The scrape marks left behind by the dinosaurs at three sites in western Colorado and one towards the east of this state attest to this fact. In the largest among these sites, 60 scrapes on a 50-meter long and 15-meter wide sandstone surface has been uncovered by paleontologists. The scientists believe the similarity of the pattern of scratches to the pattern of marks left on the ground by ground nesting birds during courtship displays could mean that these large dinosaurs also exhibited similar behaviors. Even though one might argue that these marks could represent other dinosaur habits, like digging the ground for access to food or water or for marking their territories, the scientists, after extensively studying the scrape marks, believe that the density and spacing of the marks point more towards dinosaurs engaged in ritualistic mating displays. When attempting to identify the dinosaurs to which these scrape marks belong, scientists think it could be the Acrocanthosaurus, a huge, ridge-backed theropod. With further future research, if all of the facts regarding dinosaur foreplay discovered so far appear to be futher substantiated, then we might soon be able to enjoy some recreated dinosaur dancing displays in the next blockbuster dinosaur movie.