RE: NANFA-- How Big is that Alligator ?

Bruce Stallsmith (fundulus_at_hotmail.com)
Fri, 01 Nov 2002 17:54:44 -0500

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Jan, I like your skeptical approach to alleged animal size. Maybe another
way to consider this photograph would be, "Photoshop is a powerful tool!" I
mean, this IS the Internet, the new cradle of urban myth.

I realize that I made the mistake of suspending disbelief when I first saw
the pictures. Luckily, at least KITD recognized the snakes as a western
species.

--Bruce Stallsmith
Huntsville, AL, US of A

>From: "Hoover, Jan J ERDC-EL-MS" <HOOVERJ_at_wes.army.mil>
>Reply-To: nanfa_at_aquaria.net
>To: "'nanfa_at_aquaria.net'" <nanfa at aquaria.net>
>Subject: RE: NANFA-- How Big is that Alligator ? Date: Fri, 1 Nov 2002
>16:18:03 -0600
>
>Assuming the gentleman in the picture is 200 cm (6 ft.) tall and that he is
>standing directly behind the alligator, the alligator should be
>approximately 600 cm (18 ft) total length (TL). This would be just a
>little
>smaller than the 19-20 ft figure traditionally accepted as maximum known
>size and a lot bigger than most alligators for which size is reliably
>documented. The largest alligator in Florida taken during the period
>1977-1994 (N = 76,670 !) was only 427 cm TL (14 ft) and only six other
>specimens even approached that size (> 400 cm); most were < 305 cm (< 10
>ft)
>and the largest alligator for which a skull exists is only 454 cm (14.9 ft
>TL)(Woodward et al., 1995). If this alligator were truly larger than 16
>ft,
>it would be newsworthy and well-documented. I believe that it must be
>considerably smaller.
>
>I tried three different techniques to estimate size but all assumed that
>the
>duct tape around the snout is three bands wide (15 cm). This was a
>conservatively high estimate which I used as a unit of measurement. I also
>used some measurements that I made this afternoon on a local alligator. A
>similar approach was used recently to estimate the size of the goblin shark
>recently captured in the Gulf of Mexico.
>
>1. I used calipers set for the width of the duct tape and walked them 21
>times from the tip of the tail to the tip of the snout: 315 cm (10.3 ft).
>This is probably an underestimate of the alligator's true size since the
>front half of the alligator is turned at an angle to the camera.
>
>2. I did the same from the tip of the tail to the insertion of the
>hindlegs
>and came up with 217 cm (7 ft). That measurement on a 90 cm TL alligator,
>is 54 cm. Using the 54:90 (tail:total) ratio, I extrapolated TL for the
>alligator in the picture at 362 cm or 11.9 ft. I think this is a
>reasonable
>estimate.
>
>3. Lastly, I used the local alligator's snout-width/TL ratio (1:16), and
>my
>very generous approximation of the photographed alligator's snout width (30
>cm) and came up with an estimate of 491 cm or 16 ft. I think this is an
>overestimate because of possible allometric growth of alligator heads.
>Alligator head lengths track total lengths pretty closely (Woodward et al.,
>1995), but don't older, bigger alligators have wider heads ?
>
>Also, there are two things odd about the photo: 1) there's only one (a
>truly
>remarkable animal would have inspired a series of dramatic pictures; 2)
>there is no attempt to accurately represent scale (animal photographers are
>famous for including coins, lens caps, etc. as visual yardsticks). It
>would
>have been an easy, to place a cinder block or some other suitable object in
>immediate proximity to a multiply duct-taped gator and then take several
>photographs.
>
>For more information on on how big an alligator is likely to get, see:
>
>Woodward, A.R., J.H. White, and S.B.Linda. 1995. Maximum size of the
>alligator (Alligator mississippiensis). J. Herpetol. 29(4): 507-513.
>
>For more information on this alligator photo and a diifernt approach to
>estimating its size, go to: http://www.flmnh.ufl.edu/cnhc/18ftgator.html
>
>Bottomline: Big alligators are usually smaller than they appear.
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