I’ve been reading Jacob Bronowski’s 1956 Science & Human Values, with its essay, The Habit of Truth about Leonardo Da Vinci’s The Lady with a Stoat.
He explains how the painting is a pun about so much that is human: man and animal, a creation of unity. AN Wilson has posted an annotated version of this @MailOnline in 2011:
Bronowski (1908-1974) was a mathematician and anthropologist, best known for his 1973 tv series The Ascent of Man:
Searching for a truth that human and animals are closely related, Leonardo tests and explores the consequences of the relationship. In the girl and the stoat there is the long brow of the skull, the lucid eyes, the gesture of the hand and the claw, the pale complexion of both, their body language and searching interests.