For the first time the unique coloured pattern of the iris of buttonquails (Turnicidae) is described. This unique pattern is due to the presence of a dark-brown crescent in the iris below the...

Hormones have not been found in concentrations of orders of magnitude higher than nanograms per milliliter. This study reports urine concentrations of a catecholamine (norepinephrine) ranging from...

Examples of tool-use behaviours by animals outside foraging contexts are scarce and almos exclusively limited to primates. This work documents a case of tool use in the European Honey-buzzard...

Fruit colours attract animal seed dispersers, yet the causes of fruit colour diversity remain controversial. The lack of knowledge of large?scale spatial patterns in fruit colours has limited our...

The colors of primates are among the most diverse phenotypes in mammals. These colors are mostly produced by the deposition of melanin pigments in hairs. Many species show considerable variability...