This Photo of the Week showcases seals underwater. Plus, a photographer captures bugs in motion. Also, see the longest-living vertebrate on Earth.

PHOTOGRAPH BY GREG LECOEUR, NAT GEO IMAGE COLLECTION

How do seals know how long to hold their breath? A new study published in Science suggests that they can sense the amount of oxygen in their blood and change their diving behavior in response—something humans can’t do. Today’s photo, taken by Greg Lecoeur, shows the marine mammal underwater.

Related:
— 5 videos show the irresistible charm of seals
—These fish can spot their favorite divers—here's how
—Scientists capture extremely rare footage of a black seadevil

PHOTOGRAPH BY XAVI BOU

Movements of flying insects make them tough to track, but technological advances and some creative thinking have allowed Spanish photographer Xavi Bou to do just that. Which bug species created the photo above? 

A. Zebra longwing
B. Asian lady beetle
C. Two-lined spittlebug
D. Common stonefly

PHOTOGRAPH BY SERGIO RICCARDO

A LONG TIME TO GROW: Greenland sharks are the longest-living vertebrate on Earth, with lifespans thought to stretch to around 400 years (and their bodies stretch longer than a Toyota Prius). Normally, an animal can’t grow so old. Yet, the Greenland shark seems to defy this pattern. Now, scientists have gotten some new genetic clues to their longevity.

Today’s Soundtrack: Cherry Blossom Girl, Air

Thanks for reading today’s newsletter, which was edited and curated by Jennifer Baik and David Beard. It was produced by Alisher Egamov. Did someone forward this to you? Sign up here to catch our future Photos of the Week newsletters.