Scientists have revived 'zombie' bugs and viruses before that were trapped in ancient ice. One may have been 8 million years old.

• A roundworm thawed from 46,000-year-old permafrost recently started having babies.
• Scientists have previously revived ancient bacteria and prehistoric viruses that had been trapped.
• Experts say these zombie viruses could one day pose a problem for humanity.

Scientists recently revived a microscopic roundworm from 46,000-year-old Siberian permafrost that was so well preserved, it started having babies.