Joshua A. Krisch

This rare video, showing two megamouth sharks swimming off the coast of San Diego, is scientists' 'only knowledge' of the sharks' social lives.

Animals, especially those on land, can't grow indefinitely. The reason has to do with the square-cube law.

During the last ice age, which route was taken by the first humans to reach the Americas, and did they travel by foot, boat or both?

Leaves from the Permian period curled up at night, fossils of symmetrical insect bites show.

Five species of previously unknown snakes with stunning eyes were discovered in jungle trees, and one was named after Leonardo DiCaprio. But mining threatens them all.

Elephants are known for their extraordinary memories, but is it true that they never forget?

The discovery of a tightly packed nesting ground from the Cretaceous period in India suggests that titanosaurs laid eggs and left their offspring behind.

A previously unknown extinct tortoise was revealed in an investigation on these giants' evolutionary history.

Glassfrogs can render themselves nearly invisible while they sleep with a unique trick; they pack nearly 90% of their red blood into one of their organs.

A female zebra shark conceived her pups through 'virgin birth,' despite sharing a tank with two males.

Is the simplest explanation always the best one, as Occam's razor states?

If you're at sea level, or you age more slowly or faster than someone at the top of Mount Everest?

A parasite that can alter animal behavior is changing the habits of infected wolves in Yellowstone, increasing aggression and goading them into taking greater risks.

A global drop in oxygen levels about 550 million years ago led to Earth's first known mass extinction, new evidence suggests.

Staving off the worst impacts of climate change means preventing global temperatures from rising more than 1.5 degrees Celsius above preindustrial levels. But CO2 emissions are so high that we are slated to cross that line within a decade.

In cognitive tests for recognizing certain types of patterns, crows outperformed monkeys.

The rapid decline of the British-Irish Ice Sheet thousands of years ago may hold lessons for how melting ice sheets in Greenland and Antarctica will influence sea-level rise in the future.

Recent studies have linked climate change to environmental conditions that fuel hurricane season.

A megalodon tooth found suspiciously close to two fractured whale vertebrae may reflect one small whale's heroic escape from the jaws of a giant prehistoric shark.

It depends on how you define monogamy.

Epaulette sharks can use their fins to "walk" underwater and even on dry land.

We are not yet sure how long COVID-19 immunity lasts, but experts agree that there is little cause for alarm and that a vaccine will likely still be successful.

The most important ways to prevent transmission are still the same, whether SARS-CoV-2 spreads via tiny droplets or larger ones.

The first few weeks of a keto diet may come with a spate of flu-like symptoms, including nausea, fatigue and dizziness, according to a new study.