Abstract: Abstract and Summary 1. The social structure of Cape mountain zebras consists of breeding herds and bachelor groups. The breeding herds, which comprise 1 stallion, 1–5 mares and their offspring, remain stable over many years. When the stallion is displaced by another the mares usually remain together, although some herds split up. A dominance hierarchy exists, but leadership is not confined to the dominant member. Foals leave their maternal herds at a mean age of 21.9 months. The herd stallion tries to prevent foals from leaving the herd.2. Bachelor groups are not as rigidly structured as breeding herds but core groups could be identified through a Principal Components Analysis. Family ties may be important in the establishment of core groups. Bachelors succeed in becoming herd stallions when ca. 5 years old.3. The recipient of a threat moving away seems to be an adequate response. Submissive behaviour was only recorded in bachelors. Fighting is rare, with biting as an important element. Compared to plains zebras, sounds made in communication are limited. Social grooming mainly occurs between mare and foal. Grooming intention movements may be an appeasement gesture.4. An oestrus mare assumes a characteristic posture. Flehmen occurs. Urine and faeces of oestrus mares are often marked by the stallion. This cannot be explained functionally and is not restricted to eliminations of oestrus mares. Penis erection and jerking by resting stallions could serve as a warning signal, but may be masturbatory.5. The herd stallion actively herds members of his herd and reduces intraherd antagonism by means of threats. He usually leads when the herd goes to drink and brings up the rear when the herd moves away from danger.6. Play was rarely recorded.7. A challenge ritual is performed when herd stallions meet. When challenged by a herd stallion, a bachelor is submissive.8. Foals initially remain close to their mothers and have to learn the correct orientation when suckling. A single adoption was recorded.9. Individuals apparently recognise each other after long periods.10. Cape mountain zebras react to alarm signals of antelopes.11. The greater part of the day is devoted to grazing. A significantly greater percentage of the day is spent resting in winter than in summer. Cape mountain zebras mainly stand while resting, but resting in sternal or lateral recumbency also occurs. Defaecation and urination occurs throughout the day with no definite peaks.12. Grooming consists of localized muscle contractions, shaking, striking one part of the body against another or against the ground, rubbing, dust-bathing, scratching and nibbling.13. In cold weather, Cape mountain zebras seek shelter in wooded kloofs. Zusammenfassung * 1Bergzebras bilden Familien und Junggesellengruppen. Familien bestehen aus einem Hengst, 1–5 Stuten und deren Nachwuchs. Harems bleiben jahrelang unverändert. Wird der Hengst verdrängt, so bleiben die Stuten meist zusammen. Es besteht eine Rangordnung, doch führt nicht nur das dominante Tier. Fohlen verlassen die Familie mit durchschnittlich 21,9 Monaten. Der Familienhengst versucht, die Fohlen am Weggehen zu hindern. * 2Junggesellengruppen sind nicht so fest strukturiert wie die Familien, doch lassen sich Kerngruppen durch Hauptkomponentenanalyse identifizieren. Familienbeziehungen können für das Entstehen soldier Kerngruppen wichtig sein. Junggesellen können im Alter von ungefähr 5 Jahren Familienhengste werden. * 3Flucht ist offenbar die ausreichende Reaktion auf Drohung. Unterwürfiges Verhalten wurde nur bei Junggesellen beobachtet. Kämpfe sieht man selten. Bergzebras haben weniger Kommunikationslaute als Steppenzebras. Soziale Hautpflege findet meist zwischen Stute und Fohlen statt. PflegeIntentionsbewegungen können zur Streitschlichtung benutzt werden. * 4Rossige Stuten nehmen eine charakteristische Stellung ein. Flehmen kommt vor. Harn und Kot rossiger Stuten werden oft vom Hengst markiert. Erektion des Penis mit Zuckungen beim ruhenden Hengst kann entweder als Warnsignal oder als Masturbation gedeutet werden. * 5Der Hengst herdet die Mitglieder seiner Familie und bremst innerfamiliäre Aggression durch Drohen. Gewöhnlich führt er die Familie zur Tränke und verläßt als Letzter die Gefahrenzone. * 6Spielen wurde selten beobachtet. * 7Wenn Familienhengste sich treffen, findet ein Herausforderungs-Ritual statt. Junggesellen reagieren unterwürfig, wenn sie so herausgefordert werden. * 8Fohlen bleiben anfangs nahe bei der Mutter. Sie müssen die richtige Orientierung beim Säugen erlernen. Eine Adoption wurde registriert. * 9Individuen scheinen sich nach langer Zeit wiederzuerkennen. * 10Bergzebras reagieren auf die Alarmsignale von Antilopen. * 11Der größte Teil des Tages wird zum Grasen gebraucht. Im Winter gibt es signifikant längere Ruheperioden als im Sommer. Bergzebras ruhen meist stehend. Exkremente werden den ganzen Tag über ausgeschieden. Zur Körperpflege gehören örtliche Muskelkontraktionen, Schütteln, Schlagen eines Körperteils gegen einen anderen oder gegen den Boden, Reiben, Staubbaden, Kratzen und Knabbern. * 12Bei kaltem Wetter suchen Bergzebras in bewaldeten Schluchten Schutz.

Abstract: The reproductive rate and foal survival of the free-ranging ponies on Assateague Island National Seashore were studied for 8 years, 1975 to 1982. Most (52%) of the 86 foals were born in May, 13% were born in April, 22.6% in June, 10.4% in July, and less than 1% in August and September. The mean foaling rate was 57.1 +/- 3.9% and the survival rate was 88.3 +/- 3.6%. Forty-eight colts and 55 fillies were born (sex ratio 53% female). Mares less than 3 years old did not foal and the foaling rate of 3-year-old mares was only 23%, that of 4-year-old mares was 46%, that of 5-year-old mares was 53%, and 6-year-old mares was 69%. The relatively poor reproduction rate was believed to be a consequence of the stress of lactating while carrying a foal when forage quality on the island was low. The hypothesis was supported by the higher reproductive rate (74.4 +/- 2.4%) of the ponies in the Chincoteague National Wildlife Refuge on the southern part of the island. Their foals are weaned and sold in July each year. Despite the low reproductive rate on Assateague Island National Seashore , the number of ponies increased from 43 to 80, a 90% increase in the 8-year period or greater than 10%/yr. There were 24 deaths and 8 dispersals from the study area.

Abstract: Reciprocal altruism refers to the exchange of beneficial acts between individuals, in which the benefits to the recipient exceed the cost to the altruist. Theory predicts that cooperation among unrelated animals can occur whenever individuals encounter each other regularly and are capable of adjusting their cooperative behaviour according to experience. Although the potential for reciprocal altruism exists in many animal societies, most interactions occur between closely related individuals, and examples of reciprocity among non-kin are rare. The field experiments on vervet monkeys which we present here demonstrate that grooming between unrelated individuals increases the probability that they will subsequently attend to each others' solicitations for aid. Vervets appear to be more willing to aid unrelated individuals if those individuals have behaved affinitively toward them in the recent past. In contrast, recent grooming between close genetic relatives appears to have no effect on their willingness to respond to each other's solicitations for aid.

Abstract: Spiroplasmas were observed in seven species of the family Tabanidae (horse flies and deer flies). This is the fifth family of the order Diptera now known to harbor spiroplasmas. Noncultivable spiroplasmas were seen in the hemolymph of three species of the genus Tabanus, and cultivable forms were isolated from the guts of six species in three genera. Isolates from T. calens and T. sulcifrons were serologically similar and closely related to a spiroplasma in the lampyrid beetle, Ellychnia corrusca. These three isolates represent a new serogroup. Isolates from Hybomitra lasiophthalma were related to Group IV strains, while those from T. nigrovittatus and Chrysops sp. both represented new serogroups. At least some tabanids probably acquire spiroplasmas from contaminated flower surfaces. The possibility of vertebrate reservoirs for some tabanid spiroplasmas remains an open question.