Horning and Mellish: Predation on Eumetopias /ubatus by Somniosus pacificus in the Gulf of Alaska 
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Days after surgery 
Figure 1 
Postoperative abdominal temperatures transmitted from life history transmitters (LHX 
tags) implanted in Steller sea lions (Eumetopias jubatus). (A) Temperatures in 5 animals 
that did not exhibit inflammation or other apparent health challenges. The animals were 
held in temporary captivity for up to 1 month at the Alaska Sea Life Center in Seward, 
Alaska, between 2005 and 2011. (B) Elevated temperatures in 3 animals that exhibited 
postoperative pyrexia (>38.2°C) in response to localized inflammation that surrounded 
the surgical incision, and 1 animal that exhibited postoperative hypothermia (<36.0°C) 
associated with inappetence and lethargy. The gray shaded areas indicate the normal 
range of abdominal temperatures for healthy sea lions. 
imbalance and starvation (Rosen et al., 2007), the lat- 
ter indicative of inflammatory responses to immune 
challenges (Stoskopf, 2005). 
During our postoperative monitoring of captive sea 
lions, most sea lions exhibited body core temperatures 
between 36.0°C and 38.2°C (Fig. 1A). However, several 
animals that were experiencing immunological chal- 
lenges in the form of temporary, localized inflamma- 
tions around the sutures at the incision site exhibited 
repeated abdominal temperatures above 38.2°C and up 
to 39.4°C for multiple days (Fig. IB). Inflammation was 
evident in the form of visible discharge accompanied 
with localized swelling and localized elevation of sur- 
face temperatures determined with infrared thermog- 
raphy. One animal that was experiencing depressed 
appetence and lethargy exhibited reduced abdominal 
temperatures repeatedly over several days (Fig. IB). 
The temperatures of all animals returned within the 
normal range of 36.0-38.2°C before their release. Ex- 
ertion hyperthermia may temporarily elevate temper- 
atures to 39°C, but such events are limited to <1 h. 
Therefore, sustained (longer than several hours) ante- 
mortem temperatures outside of the range from 36°C 
to 38°C range should be indicative of compromised 
health conditions, such as starvation or disease. 
Immediately after the death of warm-blooded ani- 
mals, intact bodies will gradually cool over a period of 
several hours at rates proportional to initial body tem- 
perature and mass, insulation, and type, temperature, 
and flow rate of the surrounding medium (Marshall 
and Hoare, 1962). Models of algor mortis (postmortem 
cooling) have been applied in human forensic pathology 
to estimate time of death when body mass is known 
(Henssge, 1995). When time of death and cooling rates 
are known, the same models can be solved for mass. We 
previously have parameterized an algor mortis model 
for sea lions (Horning and Mellish, 2009). This sea lion 
model reasonably predicts cooling of sea lion carcasses 
in air and water (Fig. 2, D and E) and allows for es- 
timation of mass at time of death. If implanted LHX 
tags remain embedded in intact bodies after death, 
then they should record gradual cooling while in dark- 
ness and surrounded by tissue. Such temperature data 
should produce cooling curves similar to those shown in 
