Michael Rogers Oldfield Thomas (21 February 1858 – 16 June 1929) was a British zoologist.

[1][2][3] Thomas worked at the Natural History Museum on mammals, describing about 2,000 new species and subspecies for the first time.

In 1891, Thomas married Mary Kane, daughter of Sir Andrew Clark, heiress to a small fortune, which gave him the finances to hire mammal collectors and present their specimens to the museum.

[2] In 1896, when William Henry Flower took control of the department, he hired Richard Lydekker to rearrange the exhibitions,[5] allowing Thomas to concentrate on these new specimens.

"You and I in our scientific lives have seen the general knowledge of Mammals of the world wonderfully advanced – there are few or no blank areas anymore", he said in a letter to Gerrit Smith Miller Jr.[4] Officially retired from the museum in 1923, he continued his work without interruption.