Cells vary in shape and function, and while some are enormous (the ostrich egg, the largest single cell in the animal kingdom, averages six inches long and weighs about three pounds), most cells can only be seen with the help of a microscope. The smallest object the human naked eye can see is approximately one-tenth of a millimeter (0.10 mm) in size—roughly the thickness of a piece of paper (0.15 mm), and the approximate diameter diameter of a Southern white rhino egg (0.14 mm). Let's zoom in and see how other cells measure up.

Ensuring the Well-being of Black-and-White Bears

The Alliance’s Intricate Float Honored Historic Arrival of Giant Pandas

Ian Ingram, M.S., M.F.A., a conservation technology scientist for San Diego Zoo Wildlife Alliance (SDZWA) and leader of the Conservation Technology Lab, explores deep learning and its role in protecting wildlife.

This Charismatic and Intelligent Species Has Been Extinct in the Wild Since 2002

Celebrating a pivotal moment for ʻalalā conservation and Hawaiian culture.

Imagine a World Where All Life Thrives.

Hungry? These wildlife meals make Thanksgiving dinner look like a light snack.

Protecting the San Clemente Loggerhead Shrike

Nocturnal Wildlife's Sensory Superpowers