I was just asked via PM, if a Lion's age could be determined by his skull size/measurements? Although I am not aware of any factors that can 100% determine a lion's age from his skull size. IMO, it certainly can be another "indicator" as to a potential "range" in age, that is likely for a particular specimen.

Dr. Easter will have to weigh in on the exact science, as that is certainly not my area of expertise. But here's what I can tell you from looking at, judging, measuring and shooting a whole bunch of lions/lion skulls from all across southern/eastern Africa, for the past 16 yrs.

Any lion skull that I have ever seen/measured, that I was certain was from a mature/5 yr old plus lion, scored 24.5" or bigger! I'm certain I've measured over 40 lion skulls, and I have never seen one under 24", ever! The vast majority of them have been 25" plus, and several have been over 26". I personally have shot 3 lions that have skulls between 26 1/4" - 26 3/4" skulls. One from Zim, one from Zambia and one from Tanzania.

As we all know, SCI's minimum measurement requirements for all species are dreadfully low. All in the hopes of getting lots of guys to put their trophies in the "book", and thus having the opportunity to charge them for doing so. Now, please understand that I have ZERO issue with registering trophies with SCI or any other record keeping organization. Fact is, I'm all for it, just don't choose to do it myself.

What I would say however is this. I would really like to see SCI raise their minimum scoring requirements on most species, the African Lion in particular. I would feel 100% confident in saying that any lion with a 23 3/8" skull is very likely a 3 yr old lion, maybe 4 yrs old at the most! I think if we can discourage safari hunters from thinking that a 23" skull on a lion is a specimen worthy of the "record book". We would help to discourage the shooting of young/immature lions in the future.

having 4 hunts booked, i have been studying hard on aging and I too have not seen where skull size is used as the tool. I agree that a younger lion will be on the small size. Sci minimums are really low on most animals. They should look at the science on aging and make the min at least where the science says the lion is not surely young.

All bones elongate or get bigger by growth cartilage in areas called growth plates or physes. As we all know...as an animal reaches maturity...the bones stop elongating. When the bones stop elongating or growing...this means that the growth plates have matured and "closed"...they actually go completely away. Major skull growth in all species...actually takes place very early in life. The growth plates in the skull are called "sutures". The sutures in lion skulls are pretty much fused by 4 years of age making elongation beyond 4 years minimal (some elongation may occur due to bone remodeling but minimal).

So...one could conclude based on Aarons measurements of known mature lion skulls...that any skull that measures less than ~24.5" is likely from a cat 4 or less.

You and Lane did his perfectly! A calm, experience-based discussion that leads to an unavoidable conclusion re young lions.This was a polite, but unmistakable, shot across someone's bow.

I think I even see my comments on how the SCI "low ball" record book contributes to the killing of young animals.

Best,

JSM

I think it would be a great letter campaign to start. Everyone should write SCI and ask that the current importation laws coming from Tanzania say six years old so the minimum score for lions should be raised to 24.5 level.

quote:

All bones elongate or get bigger by growth cartilage in areas called growth plates or physes. As we all know...as an animal reaches maturity...the bones stop elongating. When the bones stop elongating or growing...this means that the growth plates have matured and "closed"...they actually go completely away. Major skull growth in all species...actually takes place very early in life. The growth plates in the skull are called "sutures". The sutures in lion skulls are pretty much fused by 4 years of age making elongation beyond 4 years minimal (some elongation may occur due to bone remodeling but minimal).

quote:

So...one could conclude based on Aarons measurements of known mature lion skulls...that any skull that measures less than ~24.5" is likely from a cat 4 or less.

Lane,
I feel I understand your first statement, that if a lions skull "sutures" are fused that he is most likely 4+ years. Do you have any research data confirming this 4yr number? Also, where could one get a detailed pic of a lions skull where the "sutures" are fully fused?

I do not understand your 2nd statement, I take it that by starting with "So..." you are stating that your first statement confirms Aarons assesment? Please explain.

505 - I think what Lane is saying is that a lion can still have what is considered a big/large skull, by someone like me, but can still be in the 3 - 4 yr old range. I would assume like a teen-age kid. I'm sure at 18 yrs old a teenager's head is fully grown, but his body will certainly continue to mature/change, as we all know.

My point was that I have never seen a mature lion with a "small" skull, but Lane is saying that you could see an immature lion with a "big" skull. I can't say for certain, but I believe Bwanamich would agree with Lane as well.

Aaron you interpeted my post exactly correct!

Brad,

First let me say that the published research here is small in quantity but there is a study which has been backed up by Karyl Whitman's work that says that major growth in length & width in lion skulls is finished in the 3 year old year. I used 4 to be conservative. The "growth plates" are bridged by bony growth by 5-6. But studies have shown that growth between 4 and 6 is minimal.

So to clarify the statement in which you question...Aaron has a fair bit of info to show that most skulls of mature lions approach the 25" mark and for sure most over 24.5"

Since major growth is finished by 4...a skull significantly smaller than 24.5" (which 23 6/16' would be) is "likely" to be from a cat <4 years of age.

IE: 4 year old cats already have their full skull length potential...and Aaron's data suggests that it would like likely be 24.5" or > at that time.

Please reply if you want to kick this around more.

Hi Lane,
I side with Whitmann on this. Below are some examples of 6+ y.o. lions with their skull measurements. All of these are well below 24 inches (SCI total score)and are just a few examples I quickly selected. Our records over the years show that majority of lions taken by our clients measured less than 24" despite being 6 or + y.o.! One could therefore, draw the conclusion that skull measurement is not a reliable aging criteria....


23 3/16


23 2/16


20 13/16


23 3/16

I was speaking with Karyl before I wrote that and the point I was trying to make was that lions skulls growth curves flatten out in the 3 year old year.

Our numbers of known 5 and greater were all 24.5" or greater...most >25".

Our assumption was that less than 24.5" might be an indicator of a young but obviously your data proves that wrong in your area anyway.

Next time before I write something like that I will check your data first!

Bwana - I also think you must consider geographical location/genetics of the area. I'm giving info based on lions I have measured from all over southern/eastern Africa. I do believe yours are all from the same basic geographical location?

No different than the lion aging guide we have discussed in the past. Looks great on the face, but Packer & Whitman used evidence/examples ALL from the same general area of Tanzania. Let's see one that's truly from eastern/southern Africa, and I'll bet it looks alot different?

I can believe what you say, as all areas can have genetic differences. I've also noticed as a general rule, that the further south in Africa I go, the larger the cats seem to be. Both Skull size, and body size alike! I assure you, climate/area/genetics ALL play a part in these differences from place to place. No question, the same difference can be possible when considering lions from northern/western TZ, and other areas of Africa, hundreds/thousands of miles away.

Take brown bears in Alaska as a quick example. Bears on Kodiak Island have been proven to have on average, genetically larger skulls, than the bears on the AK Peninsula, even though they are really not far from eachother at all. Body sizes don't seem to vary much. In fact, some of the bigger bodied bears have been taken on the Peninsula, but definitely some of the biggest skulls have come from the Island.

Location/geographic differences, you cannot discount em!!

I agree on the genetics part of the equation. Over the last 10 years or so, we have hunted lion across the entire regions of Tanzania, including Western Selous. Our records show that more than half of our lions skulls measured under 24". Perhaps we are measuring too........ conservatively?

I have heard that lions further South have generally larger bodies (and therefore skulls?)but have no direct experience so can't draw an accurate opinion.

Whitman's guide does show examples of KAL (known aged lions) lions from Southern Africa that correlate with the info obtained from the Tanzanian lions. This leads me to believe that the guide can be equally "useful" in other countries other than Tanzania. I do recognize that one has to take into account regional differences as well.

quote:

Originally posted by Bwanamich:
Hi Lane,
I side with Whitmann on this. Below are some examples of 6+ y.o. lions with their skull measurements. All of these are well below 24 inches (SCI total score)and are just a few examples I quickly selected. Our records over the years show that majority of lions taken by our clients measured less than 24" despite being 6 or + y.o.! One could therefore, draw the conclusion that skull measurement is not a reliable aging criteria....


23 3/16


23 2/16


20 13/16


23 3/16

Man, its like land of the baby skulls!! The one that you have listed as only 20 13/16", are you sure that's correct?? Not even 21"? How much do these lions weigh, 300lbs? Obviously I believe ya Bwana, but man those seem awfully small!