![]() "Furthermore, flying foxes don’t sleep all day they often change their positions in the tree and interact with their neighbours. Here, a visual ‘early warning’ helps survival. "A loss of blue cones is a rare event in evolution, it has been found in only a few mammals." The scientists conclude that for the three affected fruit bat genera colour vision is less crucial than for the flying foxes.įlying foxes (Pteropus) have their daytime roosts in large open treetops, where they are exposed to birds of prey (Fig. "With just one cone type, spectral discriminations are not possible, so these species must be colour blind", says Leo Peichl. Curiously, the retinas of the three other studied genera Rousettus (rousette fruit bat), Eidolon (straw coloured fruit bat), and Epomophorus (epauleted fruit bat) completely lack blue cones, they possess only green cones. With these two cone types, flying foxes have the prerequisite for dichromatic colour vision, the common mammalian condition. The studied flying fox species (genus Pteropus) were shown to have two spectral cone types, the so-called blue cones that detect short-wave light, and the so-called green cones that detect middle-to-long-wave light. "The retina of flying foxes is no ‘evolutionary quirk’, but conforms to the general mammalian blueprint that comprises rods and cones", says Müller. For example, cats and dogs only have two to four percent cones, and even the diurnal human retina contains an average of only five percent cones. "This share of cones appears small, but from studies of other night-active mammals we know that it allows daylight vision", says lead author Brigitte Müller. In addition, all species could be shown to possess cone photoreceptors, comprising about 0.5 percent of the photoreceptors. As expected, all megabats had high densities of rod photoreceptors, the prerequisite for nocturnal visual orientation. To identify the different photoreceptor types, the researchers stained the retinas of various fruit bat species with visual pigment-specific antibodies. ![]() This prompted Brigitte Müller and Leo Peichl of the Max Planck Institute for Brain Research in Frankfurt/Main and Steven Goodman from The Field Museum for Natural History in Chicago to study the photoreceptors of fruit bats with modern histological methods. Visual navigation at twilight and sometimes also during the daytime did not fit the older view that fruit bats only possess rods, the photoreceptors for night vision. On moonless nights, fruit bats cannot fly and stay hungry. During the flights to the foraging grounds at dusk and the return to the daytime roost at dawn, the animals navigate solely by vision. Fruit bats need a good sense of vision, because when they forage at night for nectar and fruit, they orient by vision and the sense of smell. They have large eyes and pronounced visual centres in the brain. In contrast to microbats, fruit bats (Fig. The mammalian order bats ( Chiroptera) has two suborders, microbats ( Microchiroptera) and fruit bats or flying foxes ( Megachiroptera). They extract images of objects in their environment using sound and can migrate hundreds of miles and return to the exact location where they started from- sometimes right down to the same branch on a tree.© Dana LeBlanc, Lubee Bat Center, Gainesville, Florida The bats in his lab provide him with some fascinating information about the social signals that bats use-a rich social repertoire of "bat language" that reveals their sophisticated processing abilities.īats also have the capacity to perform complicated tasks and according to Faure, "possess incredible memories. "They also possess exceptionally good hearing and very sophisticated sonar-the military still doesn't have sonar as good as how nature does it in bats," says Faure.įaure's research as a neuroethologist focuses on two major animal groups: echolocating bats and tympanate insects. "The reality is that all bats do indeed see," he says. 30 in The Hamilton Spectator Auditorium, will debunk the myths, provide the facts and help the audience understand that bats are beneficial to humans-and that we can indeed co-exist happily with this much maligned group of organisms.įaure has probably heard all of the misconceptions about bats and acknowledges that the most common is that bats are blind. These amazing critters have fascinated and repelled human mammals for thousands of years, but what we know about them is riddled with myths, misconceptions and misunderstanding.Įnter McMaster's own "Bat Man," Paul Faure, a neuroethologist in the Department of Psychology, Neuroscience & Behaviour whose Science in City lecture will explore The Wings of Darkness: Myths and Realities of Bats. Some are as tiny as a bumblebee, weighing about as much as a dime while the largest have wing spans approaching 1.8 metres (6 feet). ![]() They are, however, the world's only flying mammal with more than 1000 species.
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