Age-related change in spurs and spur sheaths of the platypus (Ornithorhynchus anatinus).

The article discusses the study that describes the typical course of spur and spur sheath development of the platypus Ornithorhynchus anatinus, and estimates the probability that the wrong age is assigned to unmarked animals on the basis of spur-related attributes. The study revealed that females with only one spur sheath were recorded in most months from February to October, showing the need to carefully check both hind legs when assigning age in females, as the possibility of making a mistake in the identification of juveniles as older individuals based on bilateral sheath loss increases steadily from August onwards. It showed that the use of spur-related attributes is accurate in the identification of juvenile females as first-year animals only up to the age of about nine months.