Behavior of the gray short-tailed opossum (Monodelphis domestica) in the open field and in response to a new object, in comparison with the rat

Effect of light-dark changes on the locomotor activity in open field in adult rats and opossums

“…Regardless of the conditions in which the opossums' locomotor activity parameters were recorded, each phase of the opossums behaviour was characterised by high mobility and a variable pattern of exploratory transition from the periphery to the central part of the open field. These observations are consistent with previous reports [21,[25][26][27] and are closely linked to the biology of opossums, which lead a solitary and predatory lifestyle, and while hunting move fast into an open area. It can be assumed that within a natural biocenosis, such a behavioural strategy was beneficial for them and was recorded by evolution and natural selection.…”

“…Despite this, in the HR group of rats we observed an increase in active exploration over time. Our results can be explained by the phenomenon called 'habituation' [26,27]. Habituation is the reflection of a memory formed under the influence of various stimuli received during the exploration [23,24,26,27].…”

“…Furthermore, the total distance travelled by the HR rats in the first phase of the dark conditions (the time window 60-90 min) was higher than in the time 90-120 min. Many studies on exploratory behaviour showed that when an animal explores new surroundings, it exposes itself to harm as for example an attack of a predator, but on the other hand to a profit, an opportunity that the animal may find the shelter or food [25,26,27]. Therefore, within one species, intensity will vary depending on the exploratory behaviour, which is associated with the state of the organism's incentive.…”

“…Therefore, within one species, intensity will vary depending on the exploratory behaviour, which is associated with the state of the organism's incentive. Węsierska et al [26,27] showed that rats use the low risk behavioural strategy and avoid unknown open spaces. In the new open field test, rats are characterised by a strong passive-defensive reaction, which manifests itself in careful behaviours, completely different than that presented by opossums [25][26][27].…”

“…In the course of evolution, animals developed many adaptations to nocturnal life, such as the acute sense of smell or the ability to dig underground burrows and tunnels to shelter during the day [5,[27][28][29]. These adaptations were probably a result of moving into new ecological niches to avoid predators.…”