Katherine Latham

Sharks have survived all five of Earth's major mass extinctions and possess remarkable abilities, including basic numerical discrimination, long-term memory, sophisticated sensory systems and magnetic-field detection. Research also shows that some sharks can learn associations with jazz, form lasting social bonds and retain distinctive reproductive traits such as temporary umbilical scars. Their skin is covered in tiny tooth-like denticles that reduce drag, while some species develop through intrauterine cannibalism. Fossil evidence places shark ancestors roughly 450 million years ago, making them older than trees, dinosaurs, Saturn's rings and the North Star.

Sharks, ancient survivors found across the world’s oceans, display surprising abilities such as basic mathematical processing, musical preference learning, social bonding, and multiple advanced sensory systems. Their biology includes umbilical cords in certain species, intrauterine cannibalism, denticle‑covered skin that reduces drag, and electrosensory organs capable of detecting heartbeats and navigating magnetic fields. Fossil evidence places their origins hundreds of millions of years before trees, dinosaurs, and planetary features like Saturn’s rings, underscoring their long evolutionary history and resilience.

Trillions of zooplankton and other mesopelagic creatures migrate nightly from deep ocean waters to the surface, forming the planet’s largest animal migration and playing a vital role in food webs, nutrient mixing and long‑term carbon storage. Scientists describe how these organisms navigate the twilight zone, the physical challenges they face at microscopic scales and their influence on global climate regulation. Climate change, warming seas and expanding deep‑sea fishing threaten these ecosystems, prompting calls such as the IUCN’s proposal to halt mesopelagic fishing until their ecological impact is better understood.