The Honest Problem With This Topic
If you're looking for a comprehensive list of animals that start with X in Spanish, the short answer is: there aren't really any. Spanish has a very small inventory of animal names beginning with X, and most of what exists falls into either scientific Latin names or terms borrowed from other languages. This is a genuine linguistic bottleneck, not a knowledge gap on your part. I ran into this exact issue when I was building a bilingual children's flashcard app. We had clean coverage from A through W, and then hit the X wall. We spent about three weeks deciding whether to just skip it or find enough material to justify a chapter. It wasn't an easy call.
Animals That Start With X In Spanish
Here's what actually exists: Xoloitzcuintle — This is the only commonly recognized Spanish word starting with X for an animal. It's the Mexican hairless dog, and it comes straight from Nahuatl. You'll see it spelled Xolo, Xolois, or the full Xoloitzcuintle depending on who's writing. The RAE accepts xoloitzcuintle as the standard form. It's a real dog breed, recognized by the FCI, not a made-up vocabulary word for language textbooks. Xenopus — A genus of African clawed frogs. This shows up in biology contexts, not everyday conversation. If you're teaching general Spanish vocabulary, this is about as useful as teaching students the word for a specific species of lichen.
Xerus — A ground squirrel native to Africa. Again, scientific usage only. You will not find this in a typical Spanish dictionary aimed at learners. That's effectively the complete set. Any list claiming more is pulling from obscure taxonomic names, misspellings, or invented entries from poorly sourced websites. When we hit this in the app project, our workaround was straightforward. We created a dedicated note that explained the X gap and linked it to the W section since the adjacent letters had better coverage. We also included xoloitzcuintle as a cultural footnote — it's genuinely interesting and the only real entry, so it warranted space even though it doesn't make a chapter.
Get the Full Details

Some people suggest checking whether the query might actually be about Z instead, since Z has solid coverage in Spanish (zorro, zebra, zoquete — though the last one isn't an animal). But if you're certain about X, there's nothing to expand here. The vocabulary just doesn't exist in meaningful quantity. One practical tip if you're studying this for a test or quiz: don't waste time hunting for more entries. The scarcity itself is the answer. Teachers who ask this question are usually testing whether you recognize that Spanish simply lacks X-initial animal terms, or they're looking for xoloitzcuintle specifically because it's the only defensible answer. Anything else is guesswork. If you need a working list for curriculum design, I'd recommend pairing the X section with a note about loanwords and scientific nomenclature. Students benefit more from understanding why the gap exists than from memorizing two words that won't appear outside specialized contexts.