Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A terrain treadmill to study animal locomotion through large obstacles   A major challenge to understanding locomotion in complex 3-D terrain with
large obstacles is to create tools for controlled, systematic lab experiments.
Existing terrain arenas only allow observations at small spatiotemporal scales
(~10 body length, ~10 stride cycles). Here, we create a terrain treadmill to
enable high-resolution observations of animal locomotion through large
obstacles over large spatiotemporal scales. An animal moves through modular
obstacles on an inner sphere, while a rigidly-attached, concentric, transparent
outer sphere rotated with the opposite velocity via closed-loop feedback to
keep the animal on top. During sustained locomotion, a discoid cockroach moved
through pillar obstacles for 25 minutes ($\approx$2500 strides) over 67 m
($\approx$1500 body lengths), and was contained within a radius of 4 cm (0.9
body length) for 83% of the duration, even at speeds of up to 10 body length/s.
The treadmill enabled observation of diverse locomotor behaviors and
quantification of animal-obstacle interaction.

12
The categories of this paper are: nucl-th
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
13
The categories of this paper are: quant-ph
16
The categories of this paper are: stat
21
The categories of this paper are: adap-org
18
The categories of this paper are: econ
20
The categories of this paper are: acc-phys
11
The categories of this paper are: hep-lat
17
The categories of this paper are: q-fin
14
The categories of this paper are: math-ph
37
The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
24
The categories of this paper are: dg-ga
7
The categories of this paper are: hep-th
32
The categories of this paper are: atom-ph