Arboreal animals and their adaptational features

Introduction

• Tree living animals which lead an arboreal mode of life.
• They are classified into three types based on the adaptation to the arboreal or scansorial mode of life.

1. Wall and rock climbers

• Provided with claws and adhesive discs in their limbs.
• They can easily move on the plain surfaces of the walls.
• Kangaroos use their tail as a balancing pole to leap from rock to rock.
• Gecko-Lizard is a typical example of wall climber.

2. Terrestrio-Arboreal forms

• Usually nest on the trees.
• Periodically makes visit to the ground for gathering foods.
• E.g, sloth bear, rodents, African flying squirrel.

3. Arboreal forms

• Usually tree dwellers.
• Further divided as:

a) Branch runners

b) Forms suspended beneath branches and

c) Forms swinging by the forelimbs.

• They possess following adaptations:

i) Strong chest and ribs

• They have strong chest, ribs and limb girdles.
• Thorax is sub-circular in shape and the ribs have greater curvature.

ii) Strong girdle bones

• Pelvic and pectoral girdles are strong to support the body weight during climbing and hanging.
• Ilium of pelvic girdle is very broad and it serves to support the viscera.

iii) Grasping type of feet

• Feet are prehensile or non-prehensile type.
• Adhesive pads are present in many forms on the tips of the digits or underneath the sole of feet.
• Lamellae might be present in some cases on the ventral side of the digits.
• It helps to create vacuum to stick to the surface.

iv) Stout body

• Stout and laterally compressed body is present.
• Such body offers the least resistance while running.

v) Prehensile tail

• It is one of the common features among the arboreal forms.
• It is very long and used to balance the body during locomotion.
• e.g., primates, opposums, pit vipers, etc.
• Branch runners- squirrel, marsupials, lemurs, etc.
• Forms suspended beneath the branches- sloths, bats, etc.
• Forms swinging by the forelimbs- primates (gibbons and apes).

vi) Protrusible tongue

• Long protrusible tongue makes them easy to catch the prey.

vii) Presence of neck

• Neck helps to locate preys and enemies as it provides mobility to the head which enhances the efficiency of eyes.

viii) Claws

• Digits are with sharp and well developed claws.
• Help the animal in walking and climbing on branches of tree and other vertical surfaces.

ix) Changeable body colour

• Can change their body colour.
• Protect the animals to hide from the enemies.
• Phenomenon is called mimicry.

References:   

i) https://www.biologyonline.com/dictionary/arboreal#:~:text=The%20arboreal%20animals%20have%20adapted,especially%20on%20the%20forest%20canopy.  

ii) https://www.plt.org/educator-tips/animals-live-trees  

Arboreal animals and their adaptational features