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of the giraffe. (The animal care staff first trained
the giraffe to allow the fitting, then to ignore the
device and not remove it.) The device provided
around-the-clock data on recumbency, or when
and for how long the animal was lying down.
According to research on cattle, recumbency sig-
nals an animal is comfortable in its environment.
All three welfare-monitoring techniques were
used during one month in the summer and a
month in the winter. Miller and his team analyzed
the data, comparing the findings from winter
when the giraffe remained indoors, and summer
when they spent most of their time outdoors.
“In general, we saw some individual differenc-
es,” said Miller, “but there were no patterns across
all giraffe. There was no clear pattern that sig-
naled negative effects on welfare from housing
the animals indoors during the winter.”
Additional efforts are in process to repeat
the study to include a greater number of animals
from other institutions.

An Evolving Science
When Lance Miller arrived at Brookfield Zoo in
2014, he brought fresh ideas with him. “I’ve tried
to challenge myself and the others to think about
things in a new way.”
For instance, he expanded the capabilities of
the endocrinology lab. “When I got here it was
primarily a reproductive-monitoring lab. We’re
starting to look at some novel physiological indi-
cators of welfare, as well as different biological
samples we can use to examine welfare.” In addi- Top: A reticulated giraffe rests at HABITAT AFRICA! THE SAVANNAH. A recumbent position—sitting or lying
tion to samples of feces, urine, saliva, and blood, down—signals that a giraffe is at ease.
new biomarkers may include feathers, scales, Bottom: An animal care specialist trains a giraffe to wear an activity tracker for the giraffe study.
and hair.
Back at his previous job as a researcher at Zeigler agrees. “Without experiencing different levels of stress,
the San Diego Zoo Institute for Conservation animals can’t survive. Spikes in stress levels allow animals to
Research, Miller became interested in indicators build stamina to help predators chase down prey and prey escape
of positive animal welfare. Historically, animal predators. It helps build immune systems. What you need to be
welfare research focused on demonstrating that concerned about is when stress levels remain high at all times,
an animal is not doing poorly. because animals then begin to experience deleterious effects.”
Researchers were primarily interested in For new ideas, animal welfare scientists are studying research
indicators of negative animal welfare, particularly on humans—particularly research on biomarkers associated with
glucocorticoid metabolites. They also tended to positive emotional states. “We’re starting to look at the cortisol
focus on animal behaviors—aggression, stereotyp- to DHEA ratio,” said Miller. DHEA is the abbreviated name
ic behaviors, and self-injury, for example—that of a hormone associated with emotional resilience in humans.
could indicate an animal was doing poorly. “In humans, if the ratio is low, it typically means you’re in a
“But the absence of the negative does not good emotional state. If it’s high, it typically means you’re in
equate to the positive,” said Miller. “A lot of a state of chronic stress. We want to know if that holds true for
people think animals shouldn’t be stressed at all. species in the zoo.” Immunoglobulin A (IgA), a marker of
To be without stress is the definition of boredom. immune system function, also shows promise in measuring
Some level of stress in an animal’s life has benefits, where an animal falls in the continuum of poor to thriving.
such as improved cognitive functioning.”
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