What did the Sichuan quake zone animals know–and how soon did they know it?

From ANIMAL PEOPLE, June 2008:

BEIJING–Unusual animal behavior was widely noted before the
May 12, 2008 Sichuan earthquake, but how much of it might have
anticipated the quake is anyone’s guess.
“Three days before the earthquake, thousands of toads roamed
the streets of Mianzhu, a hard-hit city where at least 2,000 people
have been reported killed,” wrote Henry Sanderson of Associated
Press. “Mianzhu residents feared the toads were a sign of an
approaching natural disaster, but a local forestry bureau official
said it was normal, the Huaxi Metropolitan newspaper reported May 10,
two days before the earthquake.

“The day of the earthquake,” Sanderson continued, “zebras
were banging their heads against a door at the zoo in Wuhan, more
than 600 miles east of the epicenter, according to the Wuhan Evening
Paper. Elephants swung their trunks wildly, almost hitting a staff
member. The 20 lions and tigers, normally asleep at midday, were
pacing. Five minutes before the quake hit, dozens of peacocks
started screeching.”
“Physical and chemical stimuli emanate from the earth prior
to an earthquake and animals probably sense that,” Tsunami Society
president George Pararas-Carayannis told Dan Martin of Agence
France-Press. “Eventually, studies of animal behavior could lead to
better and more sophisticated sensors for use in short-term
prediction.”
Recalled Martin, “China set up a group, now disbanded,
to study” animal behavior as a predictor of earthquakes “in the
1960s. It was widely credited with accurately predicting a
7.3-magnitude 1975 quake in the northeastern Liaoning province.”
Elaborated Sanderson, “In winter 1975, Chinese officials
evacuated the city of Haicheng in northeastern Liaoning, based on
reports of unusual animal behavior and changes in ground water
levels. Still, more than 2,000 people died. Strange environmental
phenomena, including changes in well water levels, were also
reported a year later before a 7.6 magnitude earthquake in Tangshan
in northeastern China that killed 240,000, said Roger Musson of the
British Geological Survey.”
Said retired biologist Huang Zhujian, who headed the team
that studied animal behavior ahead of earthquakes, “We know animals
can see an earthquake coming, but that can play only a supplemental
role. We must depend principally on geological methods, and even
those cannot clearly predict earthquakes,” he said.
“The animals were trying to tell us something. If only
we knew that, not so many people would have died,” Tangshan quake
survivor Fu Wenran, 66, told Martin.
Wrote Martin, “Fu, then a farmer on the city’s
outskirts, said dogs erupted in wild howling and barking hours before
the July 28, 1976 quake struck at 3:42 a.m. Mice and snakes
skittered around crazily in the open. Horses and cows kicked at their
stable walls.”
“People were irritable and confused. There were many
fights that night,” recalled Fu, whose wife was killed.