Bats

There is a biological emergency...so bad that the Center for Disease
Control has interrupted Dr Sheila Casper's [Dina Meyer] field research in the bat caves
of Skull Valley, Arizona to fly her to Gallup, Texas. Six days ago, two
genetically-altered flying foxes broke free from Dr Alexander McCabe's [Bob Gunton]
research laboratory. At first, they killed only animals, but now they've
begun feeding on humans. Sheila Casper, a wildlife zoologist who
specializes in bats (Chiroptera), has been called to help find the pair
before they kill more humans or contaminate other bats in the area.Aided by Sheriff Emmett Kimsey [Lou Diamond Phillips] and CDC specialist Dr Tobe Hodge [Carlos Jacott],
Sheila and her assistant Jimmy Sands [Leon] begin to search for the bats'
roosting area. The first night out, Emmett and Sheila are attacked by a
horde of them. They are able to capture one of them and plant a homing
device under its skin. When they set it free, however, hoping that it will
lead them to the roost, it is attacked and killed by the other bats, as
though they knew it was a plant. Apparently, these bats have been bred for
super-intelligence. Gallup must be evacuated, and the mayor is told to broadcast a
warning to all residents to stay indoors and secure their houses.
Unfortunately, no one listens. The bats invade the town and, within
minutes, people are grabbing guns and shooting at anything that moves,
cars are being smashed up and bursting into flames, and victims lay in the
street dying. Tobe Hodge is one of them.More help is required. The military arrives and begins evacuating the
town. They give Sheila and her bat hunters 48 hours before they start
blowing things up. Sheila sets up headquarters in the most easily secured
building in Gallup--the school. The military has promised to center the
infrared cameras of a Chromo-B340 satellite on the area around Gallop to
help locate the bat roost.
Even when the roost is located, however, how are they going to
annihilate every last bat? From the numbers they saw the other night,
there are thousands of them. Bombing the roost will only scatter them,
Sheila explains, leading to the creation of other roosts and potentiating
the problem. Poisoning them is not an option, as the most popular bat
poison (chlorofoccinol?) is only marginally effective against bats but
highly lethal to humans. Sheila thinks the best solution is to put them to
sleep by lowering the temperature in the cave. At 40 degrees F, bats begin
to hibernate. At 32 degrees, they freeze to death.Jimmy arranges for an NGIC Industrial Coolant that uses freon, carbon
dioxide, and oxygen to be dropped off as soon as the roost is located.
When the spy satellite begins sending pictures of the bats, Emmett
recognizes the area as that of the old Black Rock mine. Everything is set
to begin at 0600 hours. Except that the government has other ideas, which
don't include waiting until dawn. During the night, they wire the mine
with explosives. Unfortunately, the bats kill them all then come for
McCabe, their creator, who still has a modicum of mind control over them.
The bats want their freedom. When Sheila et al arrive at the mine the next
morning, they are informed by the military that they weren't able to turn
on the coolant unit, so the plan now is to bomb and gas the mine starting
in one hour.Sheila decides that one hour is enough time for them to get the
coolant unit started, so she and Emmett suit up and enter the mine. Jimmy
stays outside to monitor their progress and to blow up the mine entrance
should it become necessary. Although they find themselves up to their
waist in bat guano, they are successful at starting the coolant. As they
make for the exit, the bats begin to pursue. Run, run, run! The moment
they exit, Jimmy detonates the explosives.
As they drive away, an escaped bat lifts its head out of the sand on
the road. The car runs it over. Splat. [Original Synopsis by bj_kuehl]

Question: What have the two flying foxes begun feeding on?
Answer: Humans