Abstract

(…) Direct, undisturbed observations of interactions of mother and offspring in harbour porpoises (Phocoena phocoena) in the wild are extremely rare. Because harbour porpoises are seldom held and hardly breed in captivity (Blanchet et al. 2008), even observations of mother-calf interactions of porpoises under human care are uncommon (Oleksenko & Lyamin 1996, Borowska 2009, Delgado & Wahlberg 2009). The second author, by chance, encountered a unique opportunity to observe wild porpoises (mother and calf as it turned out) associated with an offshore production platform during several weeks in September 2011. Interested in the animals as the second author was, but untrained as a biologist, the observations are only descriptive in nature. However, what could be seen repeatedly, were fully undisturbed interactions between a mother and a calf in the wild. This provided unique insight in the maternal care of porpoises and other aspects of the behaviour of this species, which would be extremely difficult to obtain in ‘normal’ (e.g., survey) conditions. (…)