Photos and species summaries
Photos and article links come from Wikipedia and Wikimedia Commons. Each card shows the photographer and licence (mostly Creative Commons) and links to the original file page. Conservation status is from the IUCN Red List (global status, which can differ from local lists).
Numbers checked against sources
- Red squirrels about 287,000, grey squirrels about 2.7 million (Great Britain): Mammal Society 2018 estimates, as reported by the UK Squirrel Accord. Other older estimates exist.
- Polar bears, ~16,000 in Canada of ~26,000 worldwide (~60–65%): Government of the Northwest Territories, WWF.
- Bat species: UK has 17 breeding species (Eurobats country report). Canada has 19 recorded, 17 regular residents (Canadian Wildlife Federation).
- Grey seals, UK holds about 35% of the world population: SCOS 2021 (earlier reports said 39–45%).
- Water vole: an estimated 94% decline to 1994 and a further 30% fall in occupied range across England and Wales from 2006 to 2015 (The Wildlife Trusts).
- Canada forest: 347–362 million hectares, about 9% of the world's forests (Natural Resources Canada).
- Narwhals in Canadian waters: roughly 75–90% depending on source (WWF Canada).
Corrected after checking
- Wildcat: "fewer than 100" changed to "under 100 to ~300", since estimates vary and most are hybrids.
- UK deer: "~2 million" changed to a range, because the British Deer Society says nobody knows (Mammal Society 2018: 650,000 to 1.47 million).
- Canada's wolf count: removed the "60,000" figure, because I couldn't find an official national estimate. British Columbia alone is estimated at ~8,500 wolves.
- Canada bats: shown as 19 recorded (17 regular residents) instead of just 19.
- Grey seals 40% → 35%; polar bears "two thirds" → "~60–65%"; water vole "90%" → the sourced 94% + 30%.
- Wren and herring gull are shown as UK-only, because Canada's birds are different species (winter/Pacific wren, American herring gull).
Not independently verified
These come from general reference knowledge and I haven't checked them against a primary source. Treat them as approximate:
- Area, population and coastline figures on the comparison page (ONS, Statistics Canada, CIA World Factbook, rounded).
- Individual species weights, speeds and lifespans in the trivia, and the exact dates animals were lost from Britain.
- Extinct and lost wildlife: the dates are approximate ("roughly", "around") and Ice Age dates in particular vary between studies.
- Bird counts such as Canada geese in the UK, and the migration and hibernation dates in the calendar.
- The list of species is a curated selection and is not a complete national checklist. Rare visitors and vagrants are left out.
Spotted a mistake? Let me know and I'll fix it.