Negative encounters with brown bears are rare and mainly non-fatal. This is the main finding of this study where the authors investigated more than 600 brown bear attacks on humans in 2000-2015 across the range inhabited by the species.

Researchers have found that eggs of two fish species can survive passage through the digestive tract of waterfowl after being swallowed, and this finding may help explain the long-standing mystery of how some species of fish colonize isolated lakes and ponds.

The accumulation of the amino acid cysteine in lysosomes produces toxic substances, which are avoided by a gene (CTNS) coding for a transporter that pumps cystine out of lysosomes. Melanosomes are lysosome-related organelles that synthesize melanins, the most widespread pigments in animals. The synthesis of the orange melanin, termed pheomelanin, depends on cysteine levels because the sulfhydryl group is used to form the pigment. Pheomelanin synthesis may, therefore, be affected by cysteine...

Telomere length is a marker of cellular senescence that relates to different components of individual fitness. Oxidative stress is often claimed as a main proximate factor contributing to telomere attrition, although the importance of this factor in vivo has recently been challenged.

Tropical forests are increasingly degraded by industrial logging, urbanization, agriculture, and infrastructure, with only 20% of the remaining area considered intact. However, this figure does not include other, more cryptic but pervasive forms of degradation, such as overhunting. Here, the spatial patterns of mammal defaunation in the tropics are quantified and mapped.