Effects of the lunar cycle on the Galápagos fur seal, Arctocephalus galapagoensis
In: Oecologia, Jg. 48 H. 1, S. 85-921981
El Nino: effects of environmental stress on pinniped populations
In: Stress - auf allen Ebenen, Jg. 6, S. 103 ff.1992
Energetic limits to brood care: influences on fertility, and longterm fitness consequences
In: Verhandlungen der Deutschen Zoologischen Gesellschaft, Jg. 84, S. 79-871991
Estimating diet composition from scat analysis in otariid seals (Otariidae): is it reliable?
In: Canadian journal of zoology, Jg. 66 H. 8, S. 1865-18701988

Female aggression and male peace-keeping in a cichlid fish harem: conflict between and within the sexes in Lamprologus ocellatus
In: Behavioral Ecology and Sociobiology, Jg. 34 H. 2, S. 105-1121994
First observations on colony structure, behavior and vocal repertoire of the South American fur seal (Arctocephalus australis, Zimmermann 1783) in Peru
In: Zeitschrift für Säugetierkunde, Jg. 46, S. 310-3221981
Foraging strategies of the Galapagos Marine Iguana (Amblyrhynchus Cristatus): adapting behavioral rules to ontogenetic size change
In: Behaviour, Jg. 128 H. 3, S. 255-2791994
Foraging strategies of the marine iguana, Amblyrhynchus cristatus
In: Behavioral Ecology and Sociobiology, Jg. 18 H. 4, S. 259-2661986


The influence of separation on the pair bond in budgerigars (Melopsittacus undulatus; Aves, Psittacidae
In: Zeitschrift für Tierpsychologie, Jg. 41, S. 396-4081976
Intraspecific allometry of neonatal size in the antarctic fur seal (Arctocephalus galapagoensis)
In: Behavioral Ecology and Sociobiology, Jg. 22 H. 5, S. 361-3641988

Learning experiments on individual recognition in budgerigars (Melopsittacus undulatus)
In: Zeitschrift für Tierpsychologie, Jg. 41, S. 372-3951976
Maternal investment and sex-allocation in the Galapagos fur seal, Arctocephalus galapagoensis
In: Behavioral Ecology and Sociobiology, Jg. 19 H. 3, S. 157-1641986
The mating systems of pinnipeds and marine iguanas: convergent evolution of polygyny
In: Biological Journal of the Linnean Society, Jg. 21, S. 209-2161984

Milk of the Galápagos fur seal and sea lion, with a comparison of the milk of eared selas (Otariidae)
In: Journal of zoology, Jg. 209, S. 271-2771986
Mutual mother-pup recognition in Galápagos fur seals and sea lions: cues used and functional significance
In: Behaviour, Jg. 78 H. 1, S. 21-421981
