5. Sharks
Sharks have long fascinated scientists for their unexpectedly low cancer rates, despite their large size and long lifespans. Their cartilage is rich in compounds believed to inhibit the growth of blood vessels that feed tumors—a process known as angiogenesis. While sharks are not entirely immune to cancer, their biology continues to inspire medical research. Ongoing studies aim to unravel how these compounds work and whether they could inform new cancer treatments for humans. Learn more.