How did the lner b1 loco get the name duiker?

The first 40 locomotives of the LNER B1 class with the exception of one which was named Ralph Assheton were named after antelope and the Duiker is one of them. Amongst the others were names like Bongo, Puku, Inyala and Sassaby along with the more commonly known ones like Roedeer and Springbok.