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Title: Rodent incisors and grass Post by: em3ry on Jan 21, 2022 The defining feature of mice and rabbits is incisors that keep growing.
Mice and rabbits appear in the fossil record at exactly the same moment that grass does. Why do mice and rabbits need Ever-growing incisors in order to eat grass? Lots of animals eat grass and don't have incisors that keep growing. Title: Re: Rodent incisors and grass Post by: elmajn on Jan 21, 2022 Incisors are used for biting and cutting food. This is required for animals that predominantly eat a fibrous diet. Yes, molars are needed to chew the food, but the incisors allow for the initial cutting.
Title: Re: Rodent incisors and grass Post by: bio_man on Jan 21, 2022 The reason they don't stop growing is because unlike our teeth, their incisors don’t have roots. To keep them from growing into their brains, rodents grind their teeth against each other. This self-sharpening not only keeps the teeth short, but it also keeps the edges very sharp, almost like a chisel.
* Also, rabbits are not rodents, as some people assume them to be Title: Re: Rodent incisors and grass Post by: em3ry on Jan 22, 2022 Wikipedia says: Ruminating animals have various physiological features that enable them to survive in nature. One feature of ruminants is their continuously growing teeth. During grazing, the silica content in forage causes abrasion of the teeth. This is compensated for by continuous tooth growth throughout the ruminant's life, as opposed to humans or other nonruminants, whose teeth stop growing after a particular age. Most ruminants do not have upper incisors; instead, they have a thick dental pad to thoroughly chew plant-based food.
I didnt know that Title: Re: Rodent incisors and grass Post by: bio_man on Jan 22, 2022 Neither did I, I think I'll write a blog post (https://biology-forums.com/index.php?blog=1) out of this :)
Title: Re: Rodent incisors and grass Post by: em3ry on Jan 22, 2022 I think it means this: https://en.wikipedia.org/wiki/Hypsodont
Title: Re: Rodent incisors and grass Post by: bio_man on Jan 22, 2022 I think it means this: https://en.wikipedia.org/wiki/Hypsodont Yes, you're right. Rabbits, guinea pigs, chinchillas and degus have aradicular hypsodont teeth. The incisors of all rodents are aradicular hypsodont, while the cheek teeth are either aradicular hypsodont or brachyodont depending on the species. The aradicular hypsodont tooth never forms a true root with an apex and the tooth grows continuously throughout the animal’s life. I make that clear in the blog post I wrote just now. https://biology-forums.com/index.php?article=1662.0 |