4 ms·

Deer don't regrow antlers the way lower animals regrow limbs

42 points by gumby 4y ago

kayodelycaon 4y ago
I just kind of assumed antlers grew like nails. Sharks grow new teeth all the time. I don't see why "regeneration" would ever be involved in the first place.
- polishdude20 4y ago
  What's interesting with antlers is if one of them is cut or damaged in a certain way, when both fall off later and regrow, both will grow into the shape of the damaged antler.
  - gumby 4y ago
    Wow, that’s really interesting!
- Sharlin 4y ago
  Well, because your assumption was false. Antlers grow nothing like nails and hair which do share the same mechanism. Ruminant horns are a mix of the two, with a hard keratin shell covering living tissue.
tomrod 4y ago
I don't understand how the hypothesis that they are the same was under consideration. This seems sort of obvious to me that fingernails, antlers, hair, and other keratin growths aren't the same as growing bones and limbs. But I know little about the area -- what am I missing in my hasty, armchair thoughts?
- LinuxBender 4y ago
  I think you are right. The only difference from fingernails is that when the antlers fall off there is bleeding. I get drops of blood where I feed the deer especially when they spar cross-pack. When they shed their antlers and some of them have bloody nubs that heal then form a smooth round nub and then the cycle repeats.
  - excalibur 4y ago
    If you lose an entire fingernail, there's likely to be blood.
    - LinuxBender 4y ago
      Yup and since humans trim or pick at their nails they don't get long enough to rip out as easily. I assume people with the extreme cases of YNS probably bleed when those gnarly nails get caught on things. Deer antlers shed even when they are tiny. I have a box full of their tiny ones that a neighbor turns into artwork.
  - Sharlin 4y ago
    > I think you are right. The only difference from fingernails is that when the antlers fall off there is bleeding. This is far from the only difference, starting from the material (living bone tissue vs non-living keratin), and process of growth (the living tissue grows and branches like a tree, vs. being extruded like from a 3D printer by a special tissue at the root of the nail). Hair and nails are the same. Antlers are very unlike those two. Horns are a mixture, with a keratin shell covering living bone tissue.
    - LinuxBender 4y ago
      I do not disagree with the composition. The reason I compare them to fingernails is that when a tip breaks off the tip does not regenerate. The broken tip remains broken. The antler may continue to grow out from the base but the tip will stay gone until they shed and regrow new antlers.
      - Sharlin 4y ago
        But the point was that I don't think they grow out from the base but instead from the tips! Branching wouldn't even be possible otherwise. A broken off antler tip may not regenerate, yes, but the reason is more like it develops scar tissue over the wound rather than just being made of inanimate protein like nails are.
- klyrs 4y ago
  I have no intuition here, so I read the article: > They found a group of cells – called PMCs – believed to be crucial for limb regeneration in frogs and salamanders – to be abundant in deer antlers as well as in the tips of mouse digits. So there's some positive evidence behind the mechanism being similar -- the same sort of cells are responsible for regeneration in deer and frogs. Which leads us to the question, how similar is this process? That was investigated by the scientists, who found that the source of PMCs to be different: > However, the researchers also discovered that the PMCs in antler-generating tissues were formed by a sharply different process to lower-order vertebrates, according to the study. The article continues in some detail as to the specific differences.
- causi 4y ago
  This seems sort of obvious to me that fingernails, antlers, hair, and other keratin growths aren't the same Antlers are bone, not keratin. During the growth process they have skin, blood vessels, and nerves.
- meindnoch 4y ago
  You're confusing antlers with horns. "Each antler grows from an attachment point on the skull called a pedicle. While an antler is growing, it is covered with highly vascular skin called velvet, which supplies oxygen and nutrients to the growing bone. Antlers are considered one of the most exaggerated cases of male secondary sexual traits in the animal kingdom, and grow faster than any other mammal bone. Growth occurs at the tip, and is initially cartilage, which is later replaced by bone tissue. Once the antler has achieved its full size, the velvet is lost and the antler's bone dies. This dead bone structure is the mature antler. In most cases, the bone at the base is destroyed by osteoclasts and the antlers fall off at some point. As a result of their fast growth rate, antlers are considered a handicap since there is an immense nutritional demand on deer to re-grow antlers annually, and thus can be honest signals of metabolic efficiency and food gathering capability." https://en.wikipedia.org/wiki/Antler https://en.wikipedia.org/wiki/Antler To summarize: - antlers grow from the tip, while hair/fingernails/horns grow from the base - antlers are living bone tissue, while hair/fingernails/horns are dead keratinous tissue - antlers are made from differentiated tissues (cartilage, bone, skin, blood vessels), while hair/fingernails/horns are just a keratin matrix
- gumby 4y ago
  Others have responded as to how antlers are different. But FYI keratinocytes are quite mysterious too. How do hair and nails grow only in one direction? That’s quite strange and nobody knows.
ftxbro 4y ago
By the way, 'lower animals' isn't the preferred nomenclature in biology anymore. They have had a comparable amount of evolutionary time to specialize in their own things (maybe even effectively more if they have larger populations or smaller generation times), and they are more refined at some stuff while humans are more refined at other stuff (like advanced sweat pores and big brain). Humans: lose our ancestral abilities of limb regeneration Also humans: call our distant cousins who didn't lose those abilities as 'lower'
- deleted 4y ago
  [deleted]
- GordonS 4y ago
  Out of curiosity, what is the preferred nomenclature nowadays?
  - deleted 4y ago
    [deleted]
  - rintakumpu 4y ago
    If you want to differentiate between mammals and other vertebrates you could simply say "other vertebrates".
    - Karawebnetwork 4y ago
      Non-mammalian vertebrates also
  - emaginniss 4y ago
    Follicly challenged species or Animals of Scales (AoS)
  - tedunangst 4y ago
    Regenerative limb enjoyers.
  - bloppe 4y ago
neom 4y ago
I can't remember if it was on here I saw it or on twitter, but a Moose shaking off it's antler is one of the more... uncomfortable... things I've seen: https://www.youtube.com/watch?v=3vT2gsJ8KbY&ab_channel=GuardianNews https://www.youtube.com/watch?v=3vT2gsJ8KbY&ab_channel=Guard...
chrisco255 4y ago
Why did antlers evolve to be shed each year rather than semi-permanent structures?
- flavius29663 4y ago
  Not an expert but if I was to guess logically, it's because of their function in the first place: it's an immense waste of resources to grow them, so being able to do so proves the individual is a healthy male, worthy of passing on his genes. Growing a new set of antlers each year (and each year it's a larger structure) proves how many resources you can accumulate and then waste, kinda similar to how lawns were maintained by medieval English lords: just to show that they can waste valuable land for nothing of value. So if you think of the evolutionary pressure, there MUST have been some deer at some point that didn't shed their antlers. The question is: would a female choose a male that tries to be economical about it's resources and save the antlers for next year? Or would the female choose the male that can take that resource hit every year? It's kindof like asking present day women: do you prefer a male with a wasteful Lamborghini or a male with an economical VW or Toyota hybrid? I think we know what the answer is... Also, biology has another angle to it, but I think this could have been overcomed evolutionary: the antlers grow form the top, so in order to keep the current antlers and then still grow them, the deer would have had to keep the velvet healthy. Being such large sharp tools, used for seasonal combat, keeping the velvet could be hard. I think this wouldn't have been un-surmountable if the deer chose this strategy, but I think my first explanation might be the most likely one.
  - pazimzadeh 4y ago
    So, proof of work?
  - jancsika 4y ago
    > It's kindof like asking present day women: do you prefer a male with a wasteful Lamborghini or a male with an economical VW or Toyota hybrid? I think we know what the answer is... Would love to hear how "common knowledge" like this deals with circular dependencies. And since this is HN, please reply as quickly as possible, and only from first principles. Problem: "present day woman" turns her head to the man stepping out of the lambo, who is shorter than the man in the hybrid, so she turns her head toward the taller man, who is driving a hybrid, so she turns her head toward the man stepping out of the lambo, who is shorter...

42 points by gumby 4y ago

I just kind of assumed antlers grew like nails. Sharks grow new teeth all the time. I don't see why "regeneration" would ever be involved in the first place.

polishdude20 4y ago
What's interesting with antlers is if one of them is cut or damaged in a certain way, when both fall off later and regrow, both will grow into the shape of the damaged antler.
- gumby 4y ago
  Wow, that’s really interesting!
Sharlin 4y ago
Well, because your assumption was false. Antlers grow nothing like nails and hair which do share the same mechanism. Ruminant horns are a mix of the two, with a hard keratin shell covering living tissue.

tomrod 4y ago

I don't understand how the hypothesis that they are the same was under consideration. This seems sort of obvious to me that fingernails, antlers, hair, and other keratin growths aren't the same as growing bones and limbs. But I know little about the area -- what am I missing in my hasty, armchair thoughts?

LinuxBender 4y ago
I think you are right. The only difference from fingernails is that when the antlers fall off there is bleeding. I get drops of blood where I feed the deer especially when they spar cross-pack. When they shed their antlers and some of them have bloody nubs that heal then form a smooth round nub and then the cycle repeats.
- excalibur 4y ago
  If you lose an entire fingernail, there's likely to be blood.
  - LinuxBender 4y ago
    Yup and since humans trim or pick at their nails they don't get long enough to rip out as easily. I assume people with the extreme cases of YNS probably bleed when those gnarly nails get caught on things. Deer antlers shed even when they are tiny. I have a box full of their tiny ones that a neighbor turns into artwork.
- Sharlin 4y ago
  > I think you are right. The only difference from fingernails is that when the antlers fall off there is bleeding. This is far from the only difference, starting from the material (living bone tissue vs non-living keratin), and process of growth (the living tissue grows and branches like a tree, vs. being extruded like from a 3D printer by a special tissue at the root of the nail). Hair and nails are the same. Antlers are very unlike those two. Horns are a mixture, with a keratin shell covering living bone tissue.
  - LinuxBender 4y ago
    I do not disagree with the composition. The reason I compare them to fingernails is that when a tip breaks off the tip does not regenerate. The broken tip remains broken. The antler may continue to grow out from the base but the tip will stay gone until they shed and regrow new antlers.
    - Sharlin 4y ago
      But the point was that I don't think they grow out from the base but instead from the tips! Branching wouldn't even be possible otherwise. A broken off antler tip may not regenerate, yes, but the reason is more like it develops scar tissue over the wound rather than just being made of inanimate protein like nails are.
klyrs 4y ago
I have no intuition here, so I read the article: > They found a group of cells – called PMCs – believed to be crucial for limb regeneration in frogs and salamanders – to be abundant in deer antlers as well as in the tips of mouse digits. So there's some positive evidence behind the mechanism being similar -- the same sort of cells are responsible for regeneration in deer and frogs. Which leads us to the question, how similar is this process? That was investigated by the scientists, who found that the source of PMCs to be different: > However, the researchers also discovered that the PMCs in antler-generating tissues were formed by a sharply different process to lower-order vertebrates, according to the study. The article continues in some detail as to the specific differences.
causi 4y ago
This seems sort of obvious to me that fingernails, antlers, hair, and other keratin growths aren't the same Antlers are bone, not keratin. During the growth process they have skin, blood vessels, and nerves.
meindnoch 4y ago
You're confusing antlers with horns. "Each antler grows from an attachment point on the skull called a pedicle. While an antler is growing, it is covered with highly vascular skin called velvet, which supplies oxygen and nutrients to the growing bone. Antlers are considered one of the most exaggerated cases of male secondary sexual traits in the animal kingdom, and grow faster than any other mammal bone. Growth occurs at the tip, and is initially cartilage, which is later replaced by bone tissue. Once the antler has achieved its full size, the velvet is lost and the antler's bone dies. This dead bone structure is the mature antler. In most cases, the bone at the base is destroyed by osteoclasts and the antlers fall off at some point. As a result of their fast growth rate, antlers are considered a handicap since there is an immense nutritional demand on deer to re-grow antlers annually, and thus can be honest signals of metabolic efficiency and food gathering capability." https://en.wikipedia.org/wiki/Antler https://en.wikipedia.org/wiki/Antler To summarize: - antlers grow from the tip, while hair/fingernails/horns grow from the base - antlers are living bone tissue, while hair/fingernails/horns are dead keratinous tissue - antlers are made from differentiated tissues (cartilage, bone, skin, blood vessels), while hair/fingernails/horns are just a keratin matrix
gumby 4y ago
Others have responded as to how antlers are different. But FYI keratinocytes are quite mysterious too. How do hair and nails grow only in one direction? That’s quite strange and nobody knows.

ftxbro 4y ago

By the way, 'lower animals' isn't the preferred nomenclature in biology anymore. They have had a comparable amount of evolutionary time to specialize in their own things (maybe even effectively more if they have larger populations or smaller generation times), and they are more refined at some stuff while humans are more refined at other stuff (like advanced sweat pores and big brain). Humans: lose our ancestral abilities of limb regeneration Also humans: call our distant cousins who didn't lose those abilities as 'lower'

deleted 4y ago
[deleted]
GordonS 4y ago
Out of curiosity, what is the preferred nomenclature nowadays?
- deleted 4y ago
  [deleted]
- rintakumpu 4y ago
  If you want to differentiate between mammals and other vertebrates you could simply say "other vertebrates".
  - Karawebnetwork 4y ago
    Non-mammalian vertebrates also
- emaginniss 4y ago
  Follicly challenged species or Animals of Scales (AoS)
- tedunangst 4y ago
  Regenerative limb enjoyers.
- bloppe 4y ago

neom 4y ago

I can't remember if it was on here I saw it or on twitter, but a Moose shaking off it's antler is one of the more... uncomfortable... things I've seen: https://www.youtube.com/watch?v=3vT2gsJ8KbY&ab_channel=GuardianNews https://www.youtube.com/watch?v=3vT2gsJ8KbY&ab_channel=Guard...

chrisco255 4y ago

Why did antlers evolve to be shed each year rather than semi-permanent structures?

flavius29663 4y ago
Not an expert but if I was to guess logically, it's because of their function in the first place: it's an immense waste of resources to grow them, so being able to do so proves the individual is a healthy male, worthy of passing on his genes. Growing a new set of antlers each year (and each year it's a larger structure) proves how many resources you can accumulate and then waste, kinda similar to how lawns were maintained by medieval English lords: just to show that they can waste valuable land for nothing of value. So if you think of the evolutionary pressure, there MUST have been some deer at some point that didn't shed their antlers. The question is: would a female choose a male that tries to be economical about it's resources and save the antlers for next year? Or would the female choose the male that can take that resource hit every year? It's kindof like asking present day women: do you prefer a male with a wasteful Lamborghini or a male with an economical VW or Toyota hybrid? I think we know what the answer is... Also, biology has another angle to it, but I think this could have been overcomed evolutionary: the antlers grow form the top, so in order to keep the current antlers and then still grow them, the deer would have had to keep the velvet healthy. Being such large sharp tools, used for seasonal combat, keeping the velvet could be hard. I think this wouldn't have been un-surmountable if the deer chose this strategy, but I think my first explanation might be the most likely one.
- pazimzadeh 4y ago
  So, proof of work?
- jancsika 4y ago
  > It's kindof like asking present day women: do you prefer a male with a wasteful Lamborghini or a male with an economical VW or Toyota hybrid? I think we know what the answer is... Would love to hear how "common knowledge" like this deals with circular dependencies. And since this is HN, please reply as quickly as possible, and only from first principles. Problem: "present day woman" turns her head to the man stepping out of the lambo, who is shorter than the man in the hybrid, so she turns her head toward the taller man, who is driving a hybrid, so she turns her head toward the man stepping out of the lambo, who is shorter...