The suricate, an insect-eating mongoose from southern Africa. Research shows mongooses’ teeth wear according to diet. (Dr. M.E. Taylor, ROM) How animals’ teeth wear down depends on diet, researcher finds By Lorraine Brown A mammologist at the Royal On- tario Musuem in Toronto has discovered that the teeth of mongooses show patterns of wear that can be related to the animal’s diet, and how it eats. Dr. Mark Taylor, associate curator of mammalogy at the ROM, found the wear patterns on the teeth of African mongooses and closely- related animals. His discovery means that scientists will be able to find out what foods different animals eat, without having to kill them and examine their stomach contents. The analysis can be done on casts taken from the teeth of anaesthetized animals, specimen skulls, or even fossils. Dr. Taylor said that research into patterns of wear on teeth was By Pippa B. Wysong A Montreal research team has |} developed robot fingertips that allow heavy robot hands to pick up delicate objects and an inflatable robot arm that can bend around corners. : Roboticists Drs. Roman Baldur and Andre Bazergui of the Ecole Polytechnique de Montreal have made prototype Force Sensing Grippers (bubble fingertips for | robot hands) and an_ Inflatable Manipulator (a bendable, elephant- truck-like arm). _ One of the problems with robot fingers is that they are not suitable | for picking up delicate objects. Of- ten, items such as mushrooms, eggs | or fruit that are picked up by robotic hands get punctured, or else squashed. Needed were fingers that were softer and that could be adjusted to the delicacy of the operation. The Force Sensing Grippers help solve these problems by covering robot fingers with inflatable bub- bles. Depending on the type of ob- ject being handled, the bubbles can be made of material as soft as surgeons’ gloves or as hefty as bicycle inner tube rubber, says Dr. Bazergui. When picking an object up, the bubbles become slightly squished, representing, a- change in pressure. The pressure it takes to pick an ob- ject up can be determined by a gauge located underneath the bub- bles and the information fed into a computer. Operators then have a record of how much pressure or force is needed for handling certain types of objects. The bubbles will also make it Robots to get air-powered limbs easier for robot hands to pick up spherical objects because they won’t slide. Dr. Roman is also adapting the bubble fingers to pick mushrooms. The Inflatable Manipulator can reach awkward places because it can bend around corners. Dr. Bazergui likens it to an ‘‘elephant trunk’’. The manipulator is like cylin- drical balloon. It can be inflated to the desired length and then be ‘pinched’ in places to make it bend. In order to pinch the cylinder, the researchers have designed little inflatable ‘‘muscles’’ that are con- trolled by compressed air. The research has been supported by a Strategic Grant from the Natural Sciences and Engineering Research Council. (Canadian Science News) originally done on fossil teeth from primates, as part of some studies on early man, by British scientist Dr. Alan Walker in 1978. Dr. Taylor wanted to apply the same type of analysis to animals. So he examined casts of teeth from one family of mammals, the Viverridae, which ranges from the dwarf mongoose (weight 150 to 240 grams) to the 10-kilogram African civet (a cat-like animal). Dr. Taylor used skulls from collections at the ROM, the British Museum (National History) and the Museum of Comparative Zoology at Berkley, California. He made molds of the teeth with dental impression material, then made epoxy resin casts from the molds. Both the molding and casting material were extremely fine- grained, so that tiny surface details would show up on the tooth casts. Then he examined small sections of the casts with an_ eiectron microscope. By limiting his study to one family of mammals, Dr. Taylor hoped to remove factors such as different arrangements of jaw muscles and different eating behaviours that might affect tooth wear patterns. The Viverridae were ideal; they have similar teeth and jaws, but different diets — everything from fruit to in- sects, molluscs and vertebrates — and different habitats. Dr. Taylor wasn’t sure he’d find anything other than a smooth, polished surface on the teeth. But once he’d examined the specimens under the scanning electron microscope, he discovered tooth wear patterns — not visible to the naked eye — that differed according to diet. He examined the cutting surfaces of the carnassials, pre-molars in the upper jaw that are adapted to tearing flesh. These teeth are found in all members of the Viverridae, and play the same functional role. But Dr. Taylor discovered that they wear differently, depending on the animal’s diet. Those Viverridae that eat ver- tebrates had deep vertical grooves on the teeth. Those that eat mainly insects had pitted tooth surfaces. Some had both pits and grooves, in- dicating a diet of insects as well as small rodents and reptiles. A fourth group had teeth with smooth surfaces and shallow grooves at right angles to each other. Horizontal grooves indicate that the animal holds its prey with its paws and tears food off using the teeth like a sharp rake, while vertical grooves are formed from chewing, Dr. Taylor says. The relative smoothness of the tooth surfaces may be due to a polishing effect of fruit, which represents a major component of the diet of animals in this fourth group, he adds. “Many of these animals are dif- ficult to get hold of, and some are quite rare,’’ says Dr. Taylor. ‘‘An advantage of this technique is that we can work with museum specimens.”’ ' In the future, Dr. Taylor hopes to continue his research on live animals, anaesthetizing them to get tooth impressions in the field. The technique could also be used on fossil teeth from extinct species. Dr. Alan Hannam, of the Faculty of Dentistry at the University of British Columbia, provided assistance with the microscope work. =~ The research on the mongoose teeth was funded by Agriculture Canada and the Medical Research Council of Canada. (Canadian Science News) By Carolyn Hoskins A road-worthy commuter car that f gets more than triple the mileage | per litre of typical North American cars has been designed and built by the University of Saskatchewan’s | Department of Mechanical | Engineering. Designed to take a single driver to and from work, the ‘Nexus’ car conforms to Canada’s standards for crash-worthiness and is licensed to run on public roads. Here itcomes......... AS The Nexus, a lightweight, fuel-efficient co of students at the University of Saskatchewan. (Photo: Barry Hertz) Researchers build a The lightweight (340 kilograms) vehicle has been developed by a team of graduate students, directed by Professor Barry Hertz. The unconventional-looking tricyle car has two outrigger-type, covered front wheels and one power-driven rear wheel. The nosecone-style front has a surface area of only 1 square metre to minimize wind resistance. The nose is filled with plastic foam, which in crash simulations compresses to absorb the impact Sei mmuter car designed by a team lightweight, efficient automobile and protects the driver. Canadian standards require that drivers must be able to survive a head-on impact with a wall at 48 kilmetres an hour. The Nexus (‘connecting link’) is powered by a Suzuki Quad Runner 250cc, air-cooled engine and has a top speed of 145 kilmetres an hour. At 100 kilometres an hour, the car’s fuel consumption is only 2.08 - litres per 100 kilometres. Dr. Hertz says Nexus can be seen as a link between the motorcycle and the passenger car or between aircraft and a motor vehicle. Em- ploying many aerodynamic prin- ciples, the design has a drag factor (a measure of air friction) of only 0.22, while that of a typical com- mercial car would be about 0.4. The Nexus body is a composite of glass fibres, while the chassis, necessary for -road — safety requirements, is made out of aluminum. Dr. Hertz says that there has been a ‘‘fantastic’’ response from all over the world, including representatives of some major car manufacturers. Right now, each Nexus is hand built at a cost of $100,000 each. Hertz estimates that $1 billion would be required in start-up costs to make a production line version selling for about $6,000. The U of S Department of Mechanical Engineering has a worldwide reputation in designing fuel-efficient vehicles. In 1986, the department broke the record for World Fuel Economy in the Shell Fuelathon by designing a 38- kilogram vehicle that could get 2014 kilometres a litre. That car will appear in the latest edition of the Guiness Book of World Records. However, the world-record vehicle was never intended for normal use, Hertz says. What makes Nexus so exciting is “that we have demonstrated that we can get phenomenal mileage ....and there it goes...... with a normal power train by keeping the air resistance and weight down,”’ Hertz says. He sees Nexus as a catalyst to get people thinking about the concept, ‘If we can convince people that we can have crash-worthiness in a light-weight car then we will have achieved something,’’ he says. The development of Nexus was funded by a grant from Transport Canada. (Canadian Science News) Nexus incorporates construction techniques and design features often used in aircraft to reduce its weight and air resistance. (Photo: Barry Hertz)