What lives within

There are four main classes of gut-dwelling worms: tapeworms (cestodes), flukes (trematodes), roundworms (nematodes) and spiny-headed worms (acanthocephalans). In this seal, Natalia finds round and spinyheaded ones. Such creatures feed on a seal’s gut contents, then reach sexual maturity and breed in the seal’s intestines. Their eggs exit in the faeces. Then tiny, free-living larvae swim in search of an initial host, which are then eaten by fish, which, in turn, are eaten by seals. The number and type of hosts can differ between worms, but this is the basic idea.

Research on intestinal parasites has traditionally focused on those that can live in humans, and their clinical effects, plus on those affecting human livestock. The diversity of worms living in other vertebrates, especially aquatic ones, remains mysterious.

Natalia will catalogue those she’s found today according to their morphology, or potentially by examining their DNA. They will then add to the 600,000 specimens in the museum’s parasite collection, of which 1,500 were the first examples of newly discovered species.