| HUMBOLDT | German naturalist and explorer after whom a Pacific current is named |
| ALEXANDER | ___ von Humboldt, a German naturalist and scientist (9) |
| MCMURDO | Archibald ---, Scottish naval officer and polar explorer after whom a US Antarctic research station is named (7) |
| VITUSBERING | Danish explorer after whom a strait, island, sea, glacier and land bridge are named |
| HUDSON | Henry, explorer after whom a bay in North America is named (6) |
| AMPERE | Andre Marie ---, French physicist and mathematician after whom the basic SI unit of electric current is named (6) |
| MARCOPOLO | Explorer after whom Venice's international airport is named (5,4) |
| BALBOA | Spanish explorer after whom Panama's currency is named (6) |
| VESPUCCI | Amerigo _, Italian explorer after whom America is named (8) |
| LEISLER | A small black bat named after a German naturalist (7) |
| LEISLERSBAT | Insectivore named after a German naturalist born in the late 18th century (8,3) |
| OKENS | Noted German naturalist Lorenz and family |
| STELLER | Georg Wilhelm ___, the 18th-century German naturalist (7) |
| TASMAN | Explorer after setback brooded with staff (6) |
| PUFFADDER | Africa's widespread Bitis arietans, described by German naturalist Blasius Merrem in 1820 (4,5) |
| NAILED | Secured land ie after a fashion (6) |
| MEGALOMANIA | Married chap blocking a goal ie after formulation shows self-importance (11) |
| DURRELL | Naturalist and zoologist who penned The Bafut Beagles, My Family and Other Animals, Menagerie Manor and The Aye-Aye and I (7) |
| BYRDOFPRAY | Polar explorer, after getting religion? |
| NINO | El ___ (Pacific current responsible for weather upheaval) |
