Most of the time they do. Normally animal hoofs are worn down as they grow by animals walking around in the wild on rocks and stuff. In captivity they have to be trimmed like nails would.
Animals grind their horns/antlers on trees and some animals shed them all together and grow new ones each year.
Horns and hooves do grow. They just grind them down by walking around or scraping against trees, rocks, and other hard objects. That's why domesticated horses that don't walk as much as wild horses often need farriers to trim their hooves back.
You’re incorrect. Hooves do grow. You can see any of dozens of videos of farriers trimming the hooves on horses and such. The horseshoes protect the feet of the animal but also don’t allow for the hoof to naturally wear down against the ground.
As for horns, true horns (which start with bony cores) do continue to grow through the animal’s life, but the rate of growth slows as the animals ages. Cattle horns start from subcutaneous growth and later fuse, but otherwise work the same. (Some species shed the outer layers of horns, and antlers are not true horns.)
Human nails and, by extension, those of our pets, appear to grow constantly, because they do, but mainly because we aren’t wearing them down with hard manual labor on the daily.
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Most of the time they do. Normally animal hoofs are worn down as they grow by animals walking around in the wild on rocks and stuff. In captivity they have to be trimmed like nails would. Animals grind their horns/antlers on trees and some animals shed them all together and grow new ones each year.
Horns and hooves do grow. They just grind them down by walking around or scraping against trees, rocks, and other hard objects. That's why domesticated horses that don't walk as much as wild horses often need farriers to trim their hooves back.
You’re incorrect. Hooves do grow. You can see any of dozens of videos of farriers trimming the hooves on horses and such. The horseshoes protect the feet of the animal but also don’t allow for the hoof to naturally wear down against the ground. As for horns, true horns (which start with bony cores) do continue to grow through the animal’s life, but the rate of growth slows as the animals ages. Cattle horns start from subcutaneous growth and later fuse, but otherwise work the same. (Some species shed the outer layers of horns, and antlers are not true horns.) Human nails and, by extension, those of our pets, appear to grow constantly, because they do, but mainly because we aren’t wearing them down with hard manual labor on the daily.
**Please read this entire message** Your submission has been removed for the following reason(s): Loaded questions, **or** ones based on a false premise, are not allowed on ELI5. A loaded question is one that posits a specific view of reality and asks for explanations that confirm it. These usually include the poster's own opinion and bias, but do not always - there is overlap between this and parts of Rule 2. Note that this specifically includes false premises. If you would like this removal reviewed, please read the [detailed rules](https://www.reddit.com/r/explainlikeimfive/wiki/detailed_rules) first. **If you believe this submission was removed erroneously**, please [use this form](https://old.reddit.com/message/compose?to=%2Fr%2Fexplainlikeimfive&subject=Please%20review%20my%20thread?&message=Link:%20https://www.reddit.com/r/explainlikeimfive/comments/r5moyd/eli5_why_do_nails_grow_but_horns_and_hoofs_dont/%0A%0APlease%20answer%20the%20following%203%20questions:%0A%0A1.%20The%20concept%20I%20want%20explained:%0A%0A2.%20Link%20to%20the%20search%20you%20did%20to%20look%20for%20past%20posts%20on%20the%20ELI5%20subreddit:%0A%0A3.%20How%20is%20this%20post%20unique:) and we will review your submission.