Abstract: In order to determine if horses will increase their intake in response to caloric dilution, four pony geldings were fed ad lib a mixed grain diet either undiluted (3.4 Mcal/kg of digestible energy) or diluted (wt/wt) with 25% sawdust (2.6 Mcal/kg) or with 50% sawdust (1.7 Mcal/kg). The mean daily caloric intake was 17,457 kcal (3.4 Mcal diet), 17,546 kcal (2.6 Mcal diet) and 12,844 kcal (1.7 Mcal). The mean time spent eating was 246 (3.4 Mcal), 351 (2.6 Mcal), and 408 (1.7 Mcal) minutes/day. Meal size increased and meal frequency decreased with increasing dilution. The median long survivorships of intermeal intervals were 6.4 min (3.4 Mcal), 3.95 min (2.6 Mcal) and 4.91 min (1.7 Mcal). Ponies responded to caloric dilution by increasing the volume of intake to maintain caloric intake when the diet had 25% diluent. When the diet was diluted by 50%, intake was increased, but not at a rate adequate to maintain caloric intake. However, the ponies were able to maintain body weight.

Abstract: If, in a mix-up at a costume shop, a couple were issued the front half of a zebra suit and the back half of a horse, it could be considered a quagga disguise. But if the masqueraders were pressed as to whether they were more horse or more zebra, the latest biochemical research advises them to insist on zebra.
The quagga, a South African animal extinct for more than 100 years, has been a source of confusion among taxonomists. Some contend, on the basis of the quagga skins preserved in museums, that this front-striped animal is a zebra, either a fourth zebra species or a variant of the Plains zebra, whose hindquarter stripes are dim. But others have argued that the quagga's teeth and skeleton indicate that its nearest relative is the true horse.
Biochemists joined the fray last year when muscle tissue was obtained from a salt-preserved quagga pelt in a West German museum. The tissue yielded both proteins and genes that could be analyzed (SN:6/9/84, p. 356).
Now the analysis has yielded some results. According to “remarkably concordant” findings on the proteins and on the genes, the quagga was a subspecies of the Plains zebra, says Jerold M. Lowenstein of the University of California at San Francisco. He looked at the binding between a sample of quagga proteins and mixtures of antibodies that bind to blood-serum proteins of each of the extant Equus species. The quagga sample bound more of the antibodies against Plains zebra serum than against the other species. Lowenstein calculates that the quagga relationship with the Plains zebra is six times closer than its relationship with the two other zebra species.
“We had to use special techniques to show the difference,” Lowenstein told SCIENCE NEWS. “There is 99 percent identity on the protein level. All the [Equus] species diverged within the past 5 million years, which is only yesterday in evolutionary terms.”
The quagga-Plains zebra relationship is further supported by the analysis of quagga mitochondrial genes performed by Russell Higuchi and Allan Wilson at the University of California at Berkeley. They find seven times as great a difference between quagga and Mountain zebra DNA as they do between quagga and Plains zebra DNA.
“Stripes, the molecules tell us, do make a zebra,” Lowenstein concludes in the July 18 NEW SCIENTIST, “and the half-striped quagga was a Plains zebra.”

Abstract: Abstract and Summary: Since the adaptive significance of social organization is emphasized diversely in both anti-predator behaviour and food searching of birds, measures and comparisons of observational learning capacity of various species are needed. Four different experimental situations were built up for juvenile and adult individuals of tits (Parus major, P. caeruleus, P. palustris) and thrushes (Turdus merula, T. philo-melos). The birds learn more easily from conspecifics and learn easily when they already know a previous problem solving situation. The capacity of observational learning of the adult great tits surpasses that of adult blue tits and marsh tits, and that of the adult blackbirds exceeds that of the adult songthrushes. The higher performance of the great tit and blackbird can be related to their greater hemispheric index. The differences in the learning capacity of the naive individuals of the three tit species and that of the two thrush species were not significant. It is suggested, that the higher observational learning of the great tit and blackbird is evolved through maturational processes and can be reflected by their greater adaptability. Zusammenfassung: Lernen durch Nachahmung wurde in vier verschiedenen Situationen mit jungen und alten Individuen von Meisen- (Parus major, P. caeruleus, P. palustris) und Drosselarten (Turdus merula, T. philomelos) untersucht. Die Vögel lernten besser von Artgenossen und lernten leicht, wenn sie vorher bereits eine Problemlösungssituation kannten. Die Lernfähigkeit (durch Nachahmung) alter Kohlmeisen übertraf die alter Blau- und Sumpfmeisen; die Lernfähigkeit alter Amseln übertraf die alter Singdrosseln. Die höhere Leistung der Kohlmeisen und Amseln hängt mit ihrem höheren Hemisphären-Index zusammen. Naive Individuen der Meisen- und Drosselarten zeigten keine signifikanten Unterschiede in ihrer Lernfähigkeit. Es ist anzunehmen, daß die höhere Lernfähigkeit der Kohlmeise und der Amsel im Laufe der Entwicklung durch Reifungsprozesse zustande kommt und sich in ihrer höheren Anpassungsfähig-keit widerspiegelt.