Amsterdam, Van Holkema & Warendof's Uitg. Mij. N.V. , 30×21,5 cm, black-and-white photograph on cover, linen spine, 96 pp., some smudges and loose or torn pages, richly decorated with 130 black-and-white photographs. Anton Frederik Johan (Frits) Portielje (1886 – 1965) started out as as journalist, then came to work at Artis Zoo in Amsterdam and researched instinctive animial behaviour. In 1946 he was granted an honorary doctorate in animal psychology by the University of Amsterdam. This book is one of his twelve animal related publications. Scarce.