The approximate number system or «sense of number» is a crucial, presymbolic mechanism
enabling animals to estimate quantities, which is essential for survival in various contexts …

An ability to estimate quantities, such as the number of conspecifics or the size of a predator,
has been reported in vertebrates. Fish, in particular zebrafish, may be instrumental in …

Debates have arisen as to whether non-human animals actually can learn abstract non-
symbolic numerousness or whether they always rely on some continuous physical aspect of …

The numerical understanding of cichlids and stingrays was examined regarding addition
and subtraction abilities within the number space of one to five. Experiments were …

Despite their young age, zebrafish larvae have a well-developed visual system and can
distinguish between different visual stimuli. First, we investigated if the first visual …

A sense of non-symbolic numerical magnitudes is widespread in the animal kingdom and
has been documented in adult zebrafish. Here, we investigated the ontogeny of this ability …

Simple Summary This study aimed to teach the numerical sequence from 1 to 19 in the
decimal system to six chimpanzees. The participants were three mother–child pairs. The …

We assessed two aspects of numerical cognition in a group of nine captive spider monkeys
(Ateles geoffroyi). Petri dishes with varying amounts of food were used to assess relative …

Implantable sensors based on shaped biocompatible hydrogels are now being extensively
developed for various physiological tasks, but they are usually difficult to implant into small …

The ability to judge numerosity is essential to an animal's survival. Nevertheless, the number
of signals presented in a sequence is often underestimated. We attempted to elucidate the …