New paper out today in Biology Letters led by Chris Basu and with John Hutchinson, both from the Royal Vet College.
Sivatherium is an extinct Giraffid from the Plio-Pleistocene boundary (~2.5 million years ago), found near the foothills of what is today (and indeed basically was then…) the Himalayas. It’s an interesting beasty that has seen relatively little attention in the literature since it’s discovery in 1836 (though it seems to be garnering a little more attention these days).
Historically, it has been referred to as being as heavy as an African elephant. We used photogrammetry to digitize the remains held in the Natural History Museum, London, and then used convex hulling to get bounds for minimum and maximum masses (I went through the process on an actual elephant skeleton in this post).
It turns out this animal was a fair bit smaller than an African elephant, coming in at give or take 1200 kg. That still makes it likely the largest ruminant we know of however!
The lead author, Chris Basu, made a stunning image for the paper in Maya, and that’s been accepted as the cover image in Biology Letters this month:
[Edit]: The paper is fully open access, and available here: http://rsbl.royalsocietypublishing.org/content/12/1/20150940
Basu, C. Falkingham, P.L., and Hutchinson, J.R. 2016. The extinct, giant giraffid Sivatherium giganteum: skeletal reconstruction and body mass estimation. Biology Letters 12(1):20150940;
Dr Peter L. Falkingham 
I am puzzled as to why the equation has a factor of 1.206 multiplied by a density of 800.
The resultant is 964.8 ( 96.48 % of the Density of water ). Logically the density of animals
has to close to, but just under, the density of water, so they can float when crossing a river
with their nose is above water. A Similar reply can be said of Weighing Dinosaurs.
The Volume should be displayed as cubic meters of water displaced by submergence.
The mass in kilograms, and volumetric displacement in liters of water would be similar.
The weight would be subject to surface gravity, which would be lower during the times
of the largest dinosaurs.
For information, you can read Dinosaurs and the Expanding Earth – Stephen Hurrell.
In addition, I have an xcell spreadsheet that I need to do testing on that includes the
Earth Radius, density, surface gravity, fraction of current surface gravity, maximum allowable
dinosaur sizes expressed as n elephant volumes, and dinosaur weight expressed as
n elephant weights. The weight is 2/3 power of the n of the elephant volumes.
The largest dinosaurs weighed significantly less than one would expect from their
volume and mass. The range in the last 230 million years is 1 to 14.5 elephant volumes,
but the weight is from 1 to 5.9463 elephant weights. The problem is time. They seem
to be very large up to 100 MYA, but the calculation show they should only be allowed
to be very very large up to 200 MYA.
I thought I would let the Dinosaurs tell me when they could be large, and how large,
and plot maximum volumes on a time line from 230 MYA to now.