Nature's official club: members can breed together and produce fertile babies.
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Scientists announced a brand-new wild cat species — the Tilcayo tiger cat (Leopardus tilcayo) from Bolivia's cloud forests — the first new wild cat species described in over 100 years. It's slightly smaller than a house cat and confirmed by genome sequencing, published 18 Sep 2026.
The classic rule: two animals belong to the same species if they can breed and their babies can also have babies. DNA is how modern science spots new members — the tilcayo was hiding in plain sight until genetics split it from its look-alike cousins. Fun fact: the tiger-cat group went from 1 species to 5 in this very study. Species lines are blurrier than school textbooks admit.
Keep it: Lion + tiger = ligers exist — but they're sterile. Different species, nature's proof of the club rule.
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