Cats by Thomas Hunter. Original from Library of Congress. Digitally enhanced by rawpixel. Free Image from public domain license 
Peacock (1925 - 1936) by Ohara Koson (1877-1945). Original from The Rijksmuseum. Digitally enhanced by rawpixel. Free Image from public domain license 
Illustration of a giraffe from Dictionnaire des Sciences Naturelles by Pierre Jean Francois Turpin (1840). Digitally enhanced… Free Image from public domain license 
Frog by a Dandelion with Flies (1877–1938) by Jan van Oort. Original from The Rijksmuseum. Digitally enhanced by… Free Image from public domain license 
Illustration of domestic cat on a stool and three playful kittens by Gottfried Mind (1768-1814). Original from Library of… Free Image from public domain license 
Frog by anonymous (1560–1585). Original from The Rijksmuseum. Digitally enhanced by rawpixel. Free Image from public domain license 
Chimpanzee "Ham" during preflight activity with one of his handlers prior to the Mercury-Redstone 2 (MR-2) test flight which… Free Image from public domain license