Thanks for advancements in tracking technologies, scientists have discovered an intriguing behavioural trait amongst some marine species: They sometimes swim in circles.
When studying the navigational abilities of sea turtles, Tomoko Narazaki, a marine researcher at the University of Tokyo, observed that the turtles in her study would swim in circles so constantly “just like a machine.”
Using a modified version of the Stanford marshmallow test, researchers at the Marine Biological Laboratory (The University of Chicago) discovered that cuttlefish had the ability to delay gratification for a better reward—and those that were able to do it for a longer duration possessed better cognitive learning abilities.
The findings, which demonstrated the link between self-control and intelligence, was published recently in the Proceedings of the Royal Society B journal.
This finding was based on research by a team of biologists and mathematicians from Swansea University and the University of Essex. It involved 15 three-spined stickleback fish observed individually in a fish tank containing two, three or five plants in fixed positions.
Sleep is ubiquitous across the animal kingdom but despite anecdotal reports of sleep-like behaviour in nurse sharks and other seafloor-dwelling species, the question of whether sharks actually sleep has been intensely debated but remains unknown. A key criterion for separating sleep from other quiescent states is an increased arousal threshold. True sleep is characterised by a lack of movement that can be rapidly reversed and a decreased awareness of surroundings.
Zoologist Douglas Bastos from the National Institute of Amazonian Research in Manaus, Brazil, and his team have captured video footage of Volta’s electric eels hunting in groups of more than 100.
During a seven-year study of reef sharks in Tahiti, ethologist Ila France Porcher also observed the behaviours of various fish species. Here, she offers a detailed description and insights into the dynamic and mesmerising spawning events of the striated surgeonfish, which take place every year in the South Pacific.
For many years, I held a weekly feeding session for the resident reef sharks and their visitors in the study area where I observed their behaviour. If I had enough shark food, I would scatter crumbs into the water for the fish after the sharks had left. The fish knew this, so they had to wait, and while they were waiting, they were excited.
Lunge-feeding humpback whales plunge into dense schools of small fish to feed on them. However, these small fish tend to be pretty fast. So, just how do huge whales sneak up on such speedy prey if they are as huge and overbearing as a ... well, whale?
This question became the focus of a study at Stanford University. Its findings was subsequently published in the Proceedings of the National Academy of Sciences journal.
In a study involving 378 orcas (or killer whales), researchers observed the first non-human example of the "grandmother effect" in a menopausal species.
This is when post-reproductive grandmothers (in this case, orcas) assist other members of the species with their offspring, thereby improving the young ones’ chances of survival. It was found that these post-reproductive orcas had the largest beneficial impact on their grandoffspring’s survival chances.