We have reported previously that all male and female mantled howlers emigrate from natal groups at Hacienda La Pacifica, Costa Rica. In the years since that report, a small number of juveniles have stayed in the natal group without experiencing a solitary phase. Here, we present a post hoc analysis on juvenile emigration in six groups of howlers under observation for varying amounts of time bet...

Adult snails are capable of learning associatively not to perform aerial respiration and then to consolidate the acquired behaviour into long-term memory (LTM). Juvenile Lymnaea, however, perform aerial respiration significantly less often and the three-neuron circuit that drives this behaviour operates significantly differently than in it does in adults. We asked whether these ontogenic behavi...

some biological characteristics of broodstock and juvenile kutum, rutilus kutum. were investigated using data collected from the estuaries of tajen and shirood rivers (tr and sr) (southern caspian sea basin) as well as from the caspian sea in 2012. the results showed higher condition factors (cf) in the male broodstocks kutum than those estimated in the female broodstock of both tr and sr. the ...

Habitat loss and landscape fragmentation are often associated with changes in biological communities at different spatial scales. Our goal in this study was to identify fragment characteristics and environmental variables linked to palm species richness, abundance and community similarity at local and landscape spatial scales and to contrast these patterns between adults and juveniles. We sampl...

The foraging patterns and time spent on vigilance behaviour by Willow Tits (Poecile montanus) were studied under varying weather conditions in a subalpine forest in central Norway during the winters of 2009–2013. The birds adjusted their microhabitat use in pines and their vigilance levels in response to perceived risk of predation and starvation. At low temperatures, the dominating adults fora...

Recognition of suitable group members can be learned through experience or can be genetically based. To determine when learning may be important in social recognition, we compared the social recognition of juveniles and adults of 2 sympatric species of three-spined sticklebacks (Gasterosteus spp.). We altered the social environment of both species, rearing individuals with varying numbers of co...

s: We conducted field surveys to monitor the population dynamics of short-neck clam, Ruditapes philippinarum, in Hichirippu Lagoon, in eastern Hokkaido, Japan, focussing on the negative impact of extremely low temperatures during the winter on juveniles in the post-settlement period. The clam population had a short annual breeding season between September and November. The newly settled juvenil...

Desiccation is an important limiting factor in the intertidal zone. Generally decreasing seaward, desiccation stress can also be alleviated in wet microhabitats. Juvenile snails are generally more susceptible to desiccation than adults, and, for some species, juveniles must therefore hide in microhabitats to survive emersion. The transition from hiding in safe microhabitats to being able to sur...

Variations in otolith patterns, sizes and body morphometrics of jack mackerel Trachurus japonicus juveniles were investigated. Under transmitted light, translucent (W(t)) and opaque otoliths (W(o)) were detected in juveniles collected from Wakasa Bay between July 2005 and April 2006, whereas only opaque otoliths (G(o)) were detected in Goto-nada Sea individuals between May and June 2006. Three ...

In humans, auditory perception reaches maturity over a broad age range, extending through adolescence. Despite this slow maturation, children are considered to be outstanding learners, suggesting that immature perceptual skills might actually be advantageous to improvement on an acoustic task as a result of training (perceptual learning). Previous non-human studies have not employed an identica...