Circulating progesterone concentrations and ovarian functional anatomy in the African elephant (Loxodonta africana).

Mean plasma progesterone concentrations measured in pregnant and non-pregnant elephants did not differ significantly from each other because of considerable variation, particularly for stage of pregnancy. Maximum progesterone values were recorded during pregnancy (5-8 months) and declined towards term (22 months). The numbers of corpora lutea or total luteal tissue volume were not critical in maintaining progesterone secretion. An increase in plasma progesterone concentrations with the luteal phase of the ovarian cycle was evident. A possible role of the placenta in the second half of gestation is indicated by an increase in fetal progesterone concentrations towards term.

Dislocation of the elbow and its social consequences for an African elephant.

A dislocated elbow of a male elephant calf (Loxodonta africana) in the Addo Elephant National Park resulted in it being harassed by other elephants and consequently leaving its maternal herd at the age of 6 years, rather than the more usual age of 9-10 years. In the absence of large predators the elephant had survived for 9 years and had adapted its locomotion and intraspecific behaviour to its injury. The humeral joint of the affected forelimb was carried in partial extension while the cubital and carpal joints were permanently in partial flexion. Substantial secondary osteoarthritic changes, extensive fusion and compensatory remodelling of the humerus, radius and ulna had taken place together with compensatory development in the musculature. The planes of articulation of the limb bones had also been considerably rotated inward.

The development of the reproductive organs of the male giraffe, Giraffa camelopardalis.

The reproductive organs of the male giraffe differ little in morphology and histology from those of other ungulates. There is some indication that gonadal hypertrophy occurs in late fetal life. Spermatogenesis begins at 3-4 years of age and coincides with a rapid increase of testicular weight and seminiferous tubule diameter. In the fetal testis the main hormone is androsteredione (2.73 microgram/g) but in adult testes testosterone is predominant (less than 10.08 microgram/g) and delta' testosterone may also be present.