THE four rhino heads stolen from the National Museum were hunting trophies and dated back to the late 1800s and early part of the 20th Century.
Three were black rhinos, the fourth was a white rhino, and all were shot in Africa.
"They'd often send the skin back to Rowland Ward (taxidermist) after it was salted or pickled, which was where half of the British Empire sent their dead things," keeper at the Natural History Museum, Nigel Monaghan, said.
The white rhino was shot by HHR White in Kenya in 1913 and was donated by his wife to the museum.
One black rhino was shot in the Sudan and gifted by a Major CW Spinks; the second was killed in East Africa and donated by officers; while the fourth was donated by a member of the Guinness family.