Maternal human habituation enhances sons’ risk of human-caused mortality in a large carnivore, brown bears

Abstract

Human habituation of large carnivores is becoming a serious problem that generates human–wildlife conflict, which often results in the removal of animals as nuisances. Although never tested, human habituation potentially reduces the fitness of adult females by reducing their offspring’s survival as well as their own, due to an increased likelihood of human-caused mortality. Here, we tested this hypothesis in brown bears inhabiting Shiretoko National Park, Japan. We estimated the frequency of human-caused mortality of independent young (aged 1–4 years) born to mothers living in areas with different maternal levels of human habituation and different proximities to areas of human activity. The overall mortality rate was higher in males than in females, and in females living near a town than those in a remote area of park. Surprisingly, more than 70% of males born to highly habituated mothers living around a remote wildlife protection area were killed by humans; this proportion is greater than that for males born to less-habituated mothers living in almost the same area. The current study clarified that interactions among maternal human habituation, birthplace (proximity to town), age, and sex determine the likelihood of human-caused mortality of brown bears at an early stage of life.

Sick of attention: The effect of a stress‐related disease on juvenile green sea turtle behaviour in the face of intense and prolonged tourism

“…In contrast, turtles without visible FP, which moved vertically more often, might spend less continuous time at the surface partly because they were more reactive to tourist action at the surface. A decrease in reactivity to repeated disturbance, or habituation, has been demonstrated in various species of bird (Ellenberg, Mattern & Seddon, 2009;Vincze et al, 2016), mammal (Schell et al, 2018;Found, 2019;Shimozuru et al, 2020), reptile (Glaudas, 2004), and fish (Titus, Daly & Exton, 2015;Folkedal et al, 2018;Neo et al, 2018). The altered behavioural pattern demonstrated between sick and healthy turtles may lead to inaccurate conclusions about the stress levels in turtles with visible FP, which are seemingly habituated (Cyr & Romero, 2009).…”

“…Therefore, it is speculated that turtles with visible FP may have been resident in nearshore feeding grounds for a longer period of time, may have been exposed to tourist pressure for longer, and are now less reactive to tourist activity. Decreased reactivity can be a sign of chronic or severe stress, and can potentially lead to maladaptive responses, such as remaining in a dangerous or harmful situation (Boren, Gemmell & Barton, 2002; Shimozuru et al, 2020). Long‐term studies comparing the behaviour and stress hormone levels between newly recruited turtles and long‐term residents in Akumal Bay would facilitate testing the relationship between habituation and disease progression.…”

Dining from the coast to the summit: Salmon and pine nuts determine the summer body condition of female brown bears on the Shiretoko Peninsula

“…(2014) suggested that factors other than food shortages, namely the avoidance of other bears or lack of experience with humans, explain bear incidences near settlements. On the Shiretoko Peninsula, the habituation of maternal bears to humans enhances the likelihood of human–bear conflict, especially in young males in the process of dispersal (Shimozuru, Shirane, Yamanaka, et al., 2020). Therefore, it would be premature to state that food shortages alone cause human–bear conflicts in this brown bear population.…”

“…No humans inhabit the area except for one fishing settlement, and the fishermen have not excluded bears from their settlements for the past few decades. For this reason, the bears have become habituated to and thus ignore humans, which allows us to observe bears directly at close range (Shimozuru, Shirane, Yamanaka, et al., 2020). In a previous study investigating bear reproductive parameters in the Rusha area, an average of 40 individuals were observed annually, including 15 adult females and three adult males (Shimozuru et al.…”

“…Over the past decade, an average of 34 bears have been killed each year, mainly for management purposes (Kohira et al. 2009; Shimozuru, Shirane, Yamanaka, et al., 2020). In 2012 and 2015, the number of bears killed for nuisance control was 65–67, nearly twice the usual number, and peaked in August (our unpublished data).…”