The Secret to Regrowing Limbs, and Other Breakthroughs

The axolotl's talent for regeneration gets scientists thinking; dino-era ticks bite; chillin' in a Mars Ice Home; and a mushroom blooms.

These stories appear in the August 2018 issue of National Geographic magazine.

A creature that can repair and regenerate limbs and organs is helping scientists at the University of Minnesota understand why humans can’t do the same. The critically endangered axolotl—also known as the Mexican salamander—shares a type of cell, called a glial cell, with humans. If an axolotl hurts its spinal cord, its glial cells go to work to repair the nerve damage and fix the injury. The same cells in humans work to form scar tissue, which prevents nerve pathways from regenerating. Researchers hope that grasping the underlying process of how axolotls can regrow their bits will one day help us regrow ours. —Lori Cuthbert

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Bloodsuckers Even Then

Here’s proof that ticks are truly prehistoric pests: When scientists found 99-million-year-old ticks entombed in Burmese amber, one (top left) was engorged with blood. Judging by a feather entangled with another of the arachnids (center), ticks may have preyed on feathered dinosaurs in the Cretaceous period. —Lori Cuthbert

Watch: Ticks That Fed on Dinosaurs Found Trapped in Amber

Ticks might be a common sight on dogs, but they also feasted on some now-extinct animals—dinosaurs. Scientists discovered a dinosaur feather encased in pieces of Cretaceous-era amber, with a tick tangled up in the plumage. It's the first direct evidence that ticks afflicted dinosaurs and primitive birds. One of the ticks was engorged with blood when it died, but the chances of extracting dino DNA are extremely low.

How to Chill Out on the Red Planet

Settling on Mars? That radiation is a killer. To block harmful cosmic rays while letting light in, the protective habitat depicted below would use ice.

The plan: A shipment of Mars Ice Home components would land and begin to deploy. A circular array of cells would inflate and fill with water drawn from Martian resources. That would freeze into the radiation shield. Homes could be linked to form an expandable base.

NASA chose the project to be part of its 2019 MISSE-11 mission, which will test how well the home’s materials hold up by attaching them to the outside of the International Space Station. —Lori Cuthbert

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Fast Fungi

This triple-exposure photograph shows a fly agaric blooming over the span of 36 hours. Mushrooms do all their growing underground. The fruit—the part we see—emerges fully formed, unfurling rapidly once it hits air. —Natasha Daly

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