The relationship between external temperature and daily activity in a large rodent (Dasyprocta azarae) in the Brazilian Pantanal

Abstract

Link to this article: http://journals.cambridge.org/abstract_S0266467415000309How to cite this article: Bruno Cid, Luiz Gustavo R. Oliveira-Santos and Guilherme Mourão (2015). The relationship between external temperature and daily activity in a large rodent (Dasyprocta azarae) in the Brazilian Abstract: Daily activity patterns reflect interactions between circadian mechanisms and environmental stimuli. Among these stimuli, temperature can be an important factor affecting activity budgets. To sample the agouti (Dasyprocta azarae), a systematic camera-trap grid was established with 50 independent sampling sites. A circular kernel function was used to characterize the activity patterns of the agouti population. To evaluate shifts in activity as a function of mean daily temperature, the entire set of records was subdivided into smaller sets covering different temperature ranges. The activity pattern belonging to each set was characterized and compared through the overlap of their full activity (95% isopleth) and activity core (50% isopleth). Based on 400 independent records, agoutis were predominately diurnal. They shifted their activity core, while keeping their activity range (the amount of time a population remains active during the 24-h cycle) constant through the temperature gradient. The agouti demonstrated a unimodal activity pattern at lower temperatures, which became more bimodal at higher temperatures. Nevertheless, it kept its activity range constant, regardless of temperature. These results likely reflect a trade-off between activity time and thermoregulation during the diurnal period and demonstrate how the agouti can change its behaviour to achieve thermal comfort.

Plasticity in the timing of activity in the Red-rumped Agouti, Dasyprocta leporina (Mammalia: Rodentia), in the Atlantic Forest of southeastern Brazil

“…The Red-rumped Agouti has a very clear diurnal and bimodal pattern of activity in both study areas. The two intervals with the most activity, after sunrise (morning) and then before and during dusk, are similar to the daily activity patterns of agoutis in different parts of the Americas (Oliveira & Bonvicino 2006, Lambert et al 2009, Norris et al 2010, Suselbeek et al 2014, Cid et al 2015, Ferreguetti et al 2018. This pattern differs from that observed in Ecuador (Blake et al 2012) and Panama (Duquette et al 2017), where the activity pattern was unimodal.…”

“…The influence of temperature on agouti daily activity have already been proposed for Central American Agouti (Dasyprocta punctata Gray, 1842) in Panama (Lambert et al 2009) and Azara's Agouti (Dasyprocta azarae Lichtenstein, 1823) in Brazilian Pantanal (Cid et al 2015). In these areas, the agoutis may use behavioral strategies to reduce the exposure to heat during the hottest times of the day (Lambert et al 2009), and the activity pattern change across the temperature gradient during the day (Cid et al 2015). Nevertheless, the agoutis keep the daily activity range constant, with similar amount of time performing their activities regardless the temperature during the morning and in the afternoon (Cid et al 2015).…”

“…Even though mammals thermoregulate, it is clear that climate regimes (mainly low or high external temperatures) have consequences for energetics and therefore can moderate the level of activity of both diurnal and nocturnal species (Beltran & Delibes 1994, Kenagy et al 2002. The influence of temperature on agouti daily activity have already been proposed for Central American Agouti (Dasyprocta punctata Gray, 1842) in Panama (Lambert et al 2009) and Azara's Agouti (Dasyprocta azarae Lichtenstein, 1823) in Brazilian Pantanal (Cid et al 2015). In these areas, the agoutis may use behavioral strategies to reduce the exposure to heat during the hottest times of the day (Lambert et al 2009), and the activity pattern change across the temperature gradient during the day (Cid et al 2015).…”

“…In these areas, the agoutis may use behavioral strategies to reduce the exposure to heat during the hottest times of the day (Lambert et al 2009), and the activity pattern change across the temperature gradient during the day (Cid et al 2015). Nevertheless, the agoutis keep the daily activity range constant, with similar amount of time performing their activities regardless the temperature during the morning and in the afternoon (Cid et al 2015). Thus, we suggest agouti activity patterns in study areas may also be influenced by differences in the ambient temperature, especially lower temperatures at the beginning and at the end of the day in EBSL, perhaps explaining why activity is different in the mountainous region with a milder climate compared to the hotter coastal region (more than 4 o C greater on average at RNV, noting that the daily thermal amplitude may be even higher in mountainous regions).…”

Daily activity patterns of medium and large neotropical mammals in an area of Atlantic rain forest at altitude

“…2005;Lambert et al, 2009;Norris et al, 2010) The last of these studies interpreted the increased crepuscular activity as a strategy for avoiding the more intense midday heat and more active predators (ocelots) at night, while nocturnal activity had a positive relationship with the availability of fruit. In the Pantanal, agoutis were less active close to midday on hotter days and increased their activity later on during the afternoon, maintaining overall activity constant in relation to days with lower temperatures (Cid et al, 2015). In the Atlantic forest in Southeast Brazil, agouti exhibited .57 activity peaks (in the morning and afternoon) and there were no records of activity during the hottest period of the day, from 12:00 to 13:30 (Ferreguetti et al, 2018).…”