The Emperor Penguin is the only penguin species that breeds during the Antarctic winter. It treks 31–75 miles over the ice to breeding colonies, which may include thousands of penguins. The female lays a single egg, which is then incubated by the male while the female returns to the sea to feed; parents subsequently take turns foraging at sea and caring for their chick in the colony. The average lifespan of the Empire Penguin is 20 years, although observations suggest that some Emperor Penguins may live to 50 years of age.

Based on how the word “trek” is used in the passage, determine its meaning.