Body Mass Estimates: Short Faced Bears/Cave Bears

[grrraaahhh]

continued....

Oct 5, 2011 19:02:24 GMT -9 grrraaahhh said:

Oct 3, 2011 17:45:37 GMT -9 grrraaahhh said:

The earlier humerus data make up the top four (three bears total) GSFB largest humerus fossils. Two bears are from North America, the other & heaviest bear is from Argentina.


KUVP 131586: Regrettably, the distal end for this left femur is missing so the incomplete data was ignored.




UC 44686 (1st in total length of GSFB ulna fossils):

Ulna measurements

A: 591
B: -
C: 65
D: 47
E: 35.2


A. Greatest Length.
B. Proximal diameter from tip of coronoid progress to Margo dorsalis.
C. Smallest diameter from bottom of semi circular notch to Margo dorsalis..
D. Inner diameter of semi circular notch.
E. Least transverse diameter of shaft, above capitulum.




UC 44687 (2nd total length GSFB femur)

Femur Measurements:

A. 678
B. a165
C. 77
D. 62
E1. 134


A. Greatest Length.
B. Greatest proximal width.
C.Caput diameter.
D. Least transverse width of shaft.
E1. Greatest distal width over epicondyles.


Source: Kurten (1967).


Both CA specimen unpublished photos have been obtained & plans are to publish them later similar to the earlier humerus figure material. Ideally, I was hoping to obtain photos for the Hay Springs bear for a comprehensive publication but travel issues & scheduling conflict have complicated matters.



Femoral measurements (1st in total length GSFB femur fossil):

UVP 015 Lake Bonville, Utah Specimen & Material:

UVP 015/1

Greatest length: 723
Greatest proximal width: 191
Caput diameter: -
Least transverse width of shaft: 64
Greatest distal width over condyles: 152


shaggygod.proboards.com/index.cgi?board=americaspleistocene&action=display&thread=329&page=2


See reply # 22.



Keep in mind, different fossil models produce different weight estimates. There are some data I want to review. I will try to follow up more shortly.

Body Mass Estimation

• There have been few attempts to estimate the size of the ‘short-faced’ bear. Where estimates were made, often the sample size was small.
  
  
• Limb bones are responsible for supporting the animal’s weight during locomotion (Anyonge, 1993; Christiansen and Harris, 2005), thus providing the best mass estimates for extinct species. Kurt´en (1967) used the reconstructed body length and the cross-sectional area of a femoral diaphysis of a large specimen from Hay Springs for calculating its mass as between 470 and 630 kg.
  
  
• Employing Kurt'en's method, Nelson and Madsen (1983) obtained an estimate of 620–660 kg for the specimen UVP 015 from Salt Lake County (Northern Utah), based on the diaphyseal area of the femur.
  
  
  
• Christiansen (1999b) used several measurements taken in the proximal limb bones to estimate the mean mass of three specimens of A. simus as ca. 770 kg.
  
  
  Figueirido et al. (2010) measured the maximum length and least width of the diaphyseal shaft of each major limb bone in a data set of 58 specimens of the eight species of extant ursids. Log-transformed data were used for calculating least squares bivariate regression functions of body mass on each measurement. For each bear species, we used published estimates of average mass (Van Valkenburgh, 1990; Christiansen, 1999b, 2002; Egi, 2001; Anderson, 2004). The accuracy of the bivariate regression functions was evaluated from their percent prediction errors (%PE) and the percent standard error of the estimates (%SEE) following Smith (1981, 1984). Approximately one third of specimen body mass estimates approached one tonne - the author further speculates that bears of this size were more common than previously suspected.
  
  
  
• Soibelzon and Schubert (2011) obtained body mass of South American short-faced bears following the estimates by Soibelzon and Tartarini (2009) employing the allometric equations published by other authors (e.g., Van Valkenburgh,1990; Anyonge, 1993; Viranta, 1994; Christiansen, 1999; Egi, 2001). The study by Soibelzon and Tartarini (2009) compared more than sixty equations based on teeth, skull and postcranial measurements, and found the most reliable predictor of body size for large specimens was six measurements of the humerus (proposed by Anyonge, 1993; Egi, 2001; Christiansen, 1999) and one on the radius (formulated by Viranta, 1994) (for more details see Soibelzon and Tartarini, 2009). Thus, the size of the individual described here is estimated based on the preserved humerus and radius using these seven equations. The result, the Argentine specimen had an estimated body mass ranging from 983 to 2,042 kg depending on the equations considered while the mean and median body mass estimates (considering all equations) were 1,588 and 1,749 kg respectively.
  
  
  
  

More to come.....

Oct 6, 2011 20:16:26 GMT -9 grrraaahhh said:

Oct 6, 2011 6:55:18 GMT -9 @tremarctinae said:

According to what i have ridden, Indarctos Atticus would be larger than ursus speleaus, with a body mass greater than 850kg...

But i'm not sure because there were probably enormous cave bears specimens...

I moved your post, profiles are meant to be locked for staff access only (my mistake).


Conventional cave bear body mass estimates produce weight estimates lower than 850 kg however.....

The cave bear appears to have been rather similar in size to the polar bear and the large species of the brown bear, and it, thus, appears likely that the mass of exceptionally large males may have well exceeded 700 kg.

Christiansen, P. What size were Arctodus simus and Ursus spelaeus (Carnivora: Ursidae)? Annales Zoologici Fennici [Ann. Zool. Fenn.]. Vol. 36, no. 2, pp. 93-102. 1999. (1999).


FWIW, Christiansen does not support Vereshagin & Baryshnikov (1984) 1000 kg + body mass estimates for large male cave bears.


Another equation Viranta (1994) measuring humeral shaft width produced a high body mass estimate of 1316 kg for male cave bears.

Giant Short-Faced Bear & Cave Bear body mass estimates are popular/fun topics of discussion. It's easier to combine both of these topics into a single thread. So far, what's been covered materially speaking has been limited, there's quite a bit more to examine, stay tuned.....

[grrraaahhh]

Keep in mind, different fossil equations produce different weight estimates.


Employing Kurten's method, Nelson and Madsen (1983) obtained an estimate of 620–660 kg for the specimen UVP 015 from Salt Lake County (Northern Utah), based on the diaphyseal area of the femur.


UVP 015 Lake Bonville, Utah Specimen

Femoral measurement

(1st in total length GSFB femur fossils)

UVP 015/1

Greatest length: 723
Greatest proximal width: 191
Caput diameter: -
Least transverse width of shaft: 64
Greatest distal width over condyles: 152




Source: Figueirido et al. (2010).


One equation produced a low of 823 kg, another results in a high of 1109 kg, the mean is 957 kg.

[grrraaahhh]

Christiansen (1999b) used several measurements taken in the proximal limb bones to estimate the mean mass of three specimens of A. simus as ca. 770 kg.

Christiansen, P. What size were Arctodus simus and Ursus spelaeus (Carnivora: Ursidae)? Annales Zoologici Fennici [Ann. Zool. Fenn.]. Vol. 36, no. 2, pp. 93-102. 1999. (1999).


Personally speaking, I am always interested in sample size specimen details. If we are examining body mass estimates for adult bears, I want to know if we are looking at a young adult or mature adult bear because there's a notable difference in body mass between a bear that is seven years old (a young adult bear) and a bear that is thirteen years old or older (a mature bear) e.g., the Utah Lake Bonville GSFB. Taking a closer look at the GSFB Christiansen (1999b) material, we are told the following specimen details:


The calculated equations were used to predict the body masses of Arctodus simus and Ursus spelaeus. The material used of Arctodus simus consists of 4 humeri and 3 femora (Fig. 1) (at the Field Museum of Natural History in Chicago and the Los Angeles County Museum). None had been sexed, but their general large size would indicate that they were males.


"Cox (1991) and Scott and Cox (1993) showed that some large specimens were present at Rancho La Brea, but that the measurable sample is skewed towards females (the majority of adult specimens) and adolescent males, where long-bone epiphyses were not fused (S. Cox, pers. comm. to Richards, 26 July 1989; Agenbroad and Mead, 1986; Cox, 1991; Scott and Cox, 1993)."

Richards et al. (1996).


Sex biased sampling is a concern in GSFB examination. Anyhow, my examination is preliminary, I plan to follow up if possible on relating data for the FHM GSFB specimens and similarly on the LACM specimens but I am in agreement with Figueirido et al. (2010) in that the Christiansen (1999b) sample size was too small.

[grrraaahhh]

Christiansen (continued)


Ursus spelaeus


The cave bear appears to have been rather similar in size to the polar bear and the large species of the brown bear, and it, thus, appears likely that the mass of exceptionally large males may have well exceeded 700 kg.


From Ursus spelaeus, 3 humeri and 3 femora were used from females, and 3 humeri and 4 femora from males (at the Zoological Museum in Copenhagen, and the Museum National d' Histoire Naturelle in Paris).


Again, similar limited sample concern. Moreover, greater specimen detail is desired (are these young adult or mature bears etc). Sexual dimorphism is strong in cave bears and depending on location and time period, some cave bear populations produced larger bears than others. FWIW, Ursus spelaeus data for humeral bone: 324-472.5, femoral - 374-500 mm (Prat, Thibault, 1976). My guess is Christiansen's examination overlaps with these data (as the specimen samples are likely the same housed in Paris). Regrettably, greater humeral & femoral follow up will not occur until possibly post New Year.



BTW, Christiansen (1999b) says the following about Vereshchagin and Baryshnikov:

Vereshchagin and Baryshnikov (1984), on the other hand, suggested that large cave bear males may have reached, or even exceeded, body masses of no less than 1 000 kg.


Here is the actual Vereshchagin and Baryshnikov text:


"The morphological features of U. spelaeus were enormous size and weight (up to 1,000 kg); flat, bunodont molars; a bulging frontal; a powerful sagittal crest; a narrow nasal foramen; and a shortened tibia. These features suggest that the cave bear was less mobile and more vegetarian than the contemporary Ursus arctos L. Ecologically the cave bear was closely tied to caves, in which it lived and bore its young. This behavior turned out to be fatal for the species at the end of the Wurm (Wisconsin). Practically all of its remains have been found in caves; remains are virtually unknown from alluvium, loess, or covering loams."


Vereshchagin. NK & Baryshnikov. GF (1984). Quaternary mammalian extinctions in northern Eurasia. In (PS Martin & RG Klein. Eds) Quaternary Extinctions: A Prehistoric Revolution. Tucson: University of Arizona Press, pp. 483-516.


I am not sure why Christiansen incorrectly references Vereshchagin and Baryshnikov. Moreover, anyone who is dismissive of G.F. Baryshnikov as it relates to cave bears is not informed. I am not talking about P. Christiansen, rather, I am talking about some of the online/blogger comments I have read over the years. The volume of work Baryshnikov has produced on cave bears especially as it relates to sexual dimorphism is impressive by any measure .


NEXT: SUVI VIRNTA FOLLOW UP.

[grrraaahhh]

Before delving into Suvi Viranta, I think it's important to note that despite the large amount of study and attention given to the Eurasian Cave Bear; collectively speaking, there has been limited body mass estimate studies made and only an additional few analysis based on limb bone (e.g., humerus, femur, etc) examination.

[grrraaahhh]

Suvi Viranta (1994)





MATERIAL REVIEW:


CAVE BEAR

• Fossils specimen obtained from the Finnish Museum of Natural History, representing Late Pleistocene populations from the Black Sea region Nordmann cave, Ukraine.
  
  
  
• The collection contains a total of 38 femora (of which 17 are of female), 33 tibiae (15 of female), 27 humeri (14 of female), 46 radii (17 of female), 2 crania (skulls with measurable occipitalis region were only males), and 141 lower carnassials. All these were used for the study.
  
  
  

EXTANT BEARS


URSUS ARCTOS, URSUS AMERICANUS, URSUS MARITIMUS

• The material of the extant bears is from the Finnish Museum of Natural History, University of Helsinki (FMNH); Zoological Museum at University of Oulu, the Zoological Museum in Copenhagen (ZMUK); and University of Maine, Department of Anthropology (UM). All the specimens belonged to adult individuals. Both zoo and wild bears were measured and used for analysis.
  
  
  
• Ursus arctos (excluding Ursus arctos middendorffi) are Scandinavian subspecies. A total of 13 individuals were measured, 6 of them are zoo animal's. Ursus americanus are from a zoo (2 individuals) or shot wild in Maine, U.S.A. (one individual). Ursus maritimus is represented by material from Greenland (5 individuals) and a zoo (9 individuals). All the species included both females and males: 6 individuals of U. arctos arctos, 6 individuals of U. maritimus, 2 individuals of U. americanus, and one individual of U. arctos middendorffi were females.
  
  
  

To be continued.....

[yogibear]

Hello
It seems I read an article a while back by a fella named Figueirido, and Kurten -not sure on the spellings here -that tried to say that the short faced bears weren't really that impressive size wise, they were no where near previous size estimates etc... how could all the previous scientists have been so off in their calculations is my question - if indeed they were in error or is this guy mistaken? just curious to your thoughts on it

[Ursus arctos]

Warning: I haven't read the article you're discussing, so I don't really know what it said.
When was it published? Kurten makes me think decades ago?

IMO the most accurate estimates are still those of Christiansen in his 1999 article "What size were Arctodus simus and Ursus spelaeus (Carnivora: Ursidae)?", estimating average size of 700-800 kg for the species.

Estimates based on limb bone dimensions seem more reliable than condylobasal skull length, which was used in Sorkin's 2006 article "Ecomorphology of the giant short-faced bears Agriotherium and Arctodus" and produced much smaller size estimates-largest known skull: 570 kg!

All estimates can of course be thrown off by addition of more specimens.

[grrraaahhh]

I haven't had a chance to again review the material (very busy here) but I feel comfortable with the following posts:

Body Mass Estimation


"Few attempts have been made to estimate the size of the ‘short-faced’ bear. For example, Kurten (1967) used the reconstructed body length and the cross-sectional area of a femoral diaphysis of a large specimen from Hay Springs for calculating its mass as between 470 and 630 kg. Similarly, Nelson and Madsen (1983) obtained an estimate of 620–660 kg for the specimen UVP 015 from Salt Lake County (Northern Utah), based on the diaphyseal area of the femur. Finally, Christiansen (1999b) used several measurements taken in the proximal limb bones to estimate the mean mass of three specimens of A. simus as ca. 770 kg. Unfortunately, all these studies were based on a small number of specimens, which do not reflect the wide intraspecifc body mass range expected in a highly dimorphic species such as A. simus (Kurten, 1967; Cox, 1991). As indicated above, in this study we measured the maximum length and least width of the diaphyseal shaft of each major limb bone in a data set of 58 specimens of the eight species of extant ursids. Log-transformed data were used for calculating least squares bivariate regression functions of body mass on each measurement."


"The fact that one third of the specimens analyzed approached a ton suggests that individuals of this size were more common than previously suspected."


Figueirido, Borja. 2010, Demythologizing Arctodus simus, the ‘Short-Faced’ Long-Legged and Predaceous Bear that Never Was.

shaggygod.proboards.com/index.cgi?board=americaspleistocene&action=display&thread=329&page=1


and.....


Figueirido: 957 kg (same thread, see reply #5).



Lastly.......






Above: They are the largest GSFB's (mature specimens) found on both of the America's. Photo of the Kansas specimen (it's a cast replica) has not been published until now/here.

[tripoliraider]

In your opinion, would KUVP C-2427 have been a 1-ton bear?

[richardrli]

Apr 13, 2013 0:23:33 GMT -9 tripoliraider said:

In your opinion, would KUVP C-2427 have been a 1-ton bear?

1 short ton would most likely be a severe underestimate