Department of Paleontology staff members Tom Deméré and Kesler Randall measure the length of the tusk discovered at the 16th and Market project site.
With proper safeguards, water currents can be harnessed out of sight.
Barely pulled back from the brink of extinction, California condors are still being poisoned by lead-based ammunition.
Vulnerable everywhere in the wild, lions already face regional extinction.
Reef-building sponges are giving up their long-held secrets.