The Rocky Mountain locust is an extinct species of grasshopper that ranged through the western half of the United States and some western portions of Canada with large numbers seen until the end of the 19th century. Sightings often placed their swarms in numbers far larger than any other locust species, with one famous sighting in 1875 estimated at 198,000 square miles (510,000 km2) in size, weighing 27.5 million tons and consisting of some 12.5 trillion insects, the greatest concentration of animals ever speculatively guessed, according to Guinness World Records.

The Eskimo curlew, also known as northern curlew, is a species of curlew in the family Scolopacidae. It was one of the most numerous shorebirds in the tundra of western Arctic Canada and Alaska. Thousands of birds were then killed per year in the late 1800s. As there has not been a reliable sighting since 1987 or a confirmed sighting since 1963, the Eskimo curlew is considered Critically Endangered or possibly extinct. The bird was about 30 cm (12 in) long and fed mostly on insects and berries.