Ciekawostka: Elephants only sleep for two hours each day

Evidence: 73 • authority: 92

Monitoring Zoo Elephant Rumble Activity Using Combined Seismic and Acoustic Data.. The communication of African and Asian elephants based on seismic and acoustic waves has been studied for decades. However, research within anthropogenic zoo environments, particularly with respect to seismic signals, remains limited compared to studies in natural habitats. This study analyzes low-frequency elephant rumbles recorded at the Opel-Zoo near Frankfurt am Main, Germany, by comparing characteristics from datasets obtained using non-invasive, co-located seismic and infrasound sensors. Analysis of recordings from August 2024 revealed over 1350 rumbles, indicating significant temporal variability. Thes…

Evidence: 59 • authority: 92

A Dynamic Model of Microsleep and Vigilance Tradeoffs in Nesting Chinstrap Penguins.. Background Sleep in wild animals reflects both physiological regulation and ecological demands. Nesting chinstrap penguins exhibit extreme sleep fragmentation, obtaining substantial sleep through thousands of brief microsleep episodes while maintaining vigilance. Objective To examine whether a dynamic model integrating sleep regulation with ecological trade-offs can account for the fragmented sleep patterns observed in nesting chinstrap penguins. Methods We adapted a dynamic model of sleep choice in which an animal switches between sleep and wakefulness on the basis of homeostatic sleep pressure, circadian…

Evidence: 59 • authority: 72

Sleep is broadly considered a biological necessity in virtually all animals. The large majority of such taxa with documented sleep physiology are bilaterians, though there is increasing evidence of sleep or sleep-like states in non-bilaterians such as Cassiopea jellyfish and hydra (both cnidarians), and sponges. The various criteria which biologists use to define sleep states have been observed in all other animal phyla, often with profound variation in function. In all of these taxa except sponges, regulation of sleep is documented to involve genes whose transcription oscillates with time, known as circadian or clock genes. These genes and the gene networks they regulate give rise to the i…

Evidence: — • authority: 35