Dolphins produce a range of vocalizations used for echolocation and communication. These vocalizations vary with social context, environmental conditions, and external stimuli, communication, reflecting their cognitive and behavioral complexity. A study published in PLOS One on December 3, 2025 by Francesco Di Nardo at Università Politecnica delle Marche, Ancona, Italy and colleagues suggests that the frequency and duration of captive dolphin vocalizations may indicate engagement with structured activities.

Participants in a study who self-reported a stronger desire to have children showed a weaker preference for younger faces compared to those with a weaker desire to have children, according to a study published December 3, 2025 in the open-access journal PLOS One by Jingheng Li and colleagues from the University of Strathclyde, Glasgow, U.K. The preference was unrelated to the potential partners’ perceived wealth or parental prowess.

It’s no surprise that dogs benefit people’s mental health. In a paper publishing in the Cell Press journal iScience on December 3, researchers point to a reason as to why: dogs prompt changes in the collection of microbes that live in and on our bodies, resulting in an increase in mental health. 

A new study of 2,000 U.S. adults shows dark web users report much higher rates of depression, paranoia, suicidal thoughts, self-injury and digital self-harm than surface web users. People with suicidal thoughts were nearly three times more likely to use the dark web, while those engaging in self-injury or digital self-harm were up to five and 19 times more likely, respectively. Researchers suggest dark web use may reflect underlying mental health struggles and urge professionals to reach vulnerable users in these hidden spaces.