In 1956 he graduated, after three years as an assistant to Prof. Dr. Hilbrand Boschma (1893–1976), the director of the Rijksmuseum van Natuurlijke Historie, who taught Systematic Zoology at Leiden University.

She became painfully aware of his malacological interests when one day on their honeymoon in Switzerland, they were returning home late in the evening and van Bruggen found a beautiful specimen of the slug Limax cinereoniger that he wanted for his collection.

Contacts with field staff of South African National Parks brought a new focus on nature conservation, and stimulated an interest in zoos.

In 1963, at the 125th anniversary of Artis Zoo in Amsterdam, van Bruggen sent a number of rock hyraxes (Procavia capensis), as a gift from Dutch biologists working in South Africa.

Although officially employed by the University, his actual place of work was a few minutes away at the Rijksmuseum van Natuurlijke Historie, where his supervisor was Prof. Dr Leo Brongersma, director of the museum.

With the Dutch Malacological Society (Nederlandse Malacologische Vereniging, NMV), he served as Secretary (1953–1956), interim President (1970–1972) and Treasurer (1983–1986) on the Board.

[1] He retired in 1994, with a lecture entitled Semper aliquid novi ex Africam adferre, which may be translated as "there is always something new from Africa", and which may be regarded as van Bruggen's personal motto.

During their 2008 trip, van Bruggen accepted Dai Herbert's request to cooperate in revising some material collected in the Drakensberg Mountains, which allowed him to continue with his great love – land snails of South Africa.

[2] Dolf van Bruggen's wide interest in systematic biology and related fields are reflected in his numerous publications, which cover topics as diverse as marine and non-marine Mollusca, mammals, amphibians, reptiles, birds, insects, as well as zoo biology, museum collections, nature conservation, bibliographical matters, and historical accounts, apart from numerous book reviews and obituaries, to name only the fields on which he wrote more than a single contribution.

In this period, he published 18 papers, mainly on Ephemeroptera from Southeast Asia and New Guinea, and on Diptera from southern Africa, thereby introducing 14 new species and two new genera.

[1] Most of van Bruggen's scientific work has been devoted to land snails, especially those from subsaharan Africa and the islands surrounding this continent.

[1] The interest in the carnivorous family Streptaxidae was undoubtedly raised by van Bruggen's prolonged stay in South Africa, quite possibly inspired by Matthew William Kemble Connolly’s (1939)[3] impressive monograph on the South African non-marine Mollusca, in which a picture of an extremely diverse and aesthetically appealing streptaxid radiation was painted.

[1] Achatinidae are a family of rather large land snails, and, in spite of their size, one that poses tremendous taxonomic problems, and van Bruggen is one of the few people who knows his way in the chaotic taxonomy of this group.

[1] A third group that apparently has his special interest are the terrestrial operculates, formerly known as ‘Prosobranchia’, a heterogeneous assemblage of gastropods with an operculum and separate males and females (in contrast to the hermaphrodite pulmonate land snails).