Flying squirrels use a mortise-tenon structure to fix nuts on understory twigs

  1. Han Xu
  2. Lian Xia
  3. John R Spence
  4. Mingxian Lin
  5. Chunyang Lu
  6. Yanpeng Li
  7. Jie Chen
  8. Tushou Luo
  9. Yide Li
  10. Suqin Fang  Is a corresponding author
  1. Chinese Academy of Forestry, China
  2. Hainan University, China
  3. University of Alberta, Canada
  4. Sun Yat-sen University, China

Abstract

Squirrels of temperate zones commonly store nuts or seeds under leaf litter, in hollow logs or even in holes in the ground; however, in the humid rainforests of Jianfengling in Hainan, South China, we show that some flying squirrels cache elliptical or oblate nuts by hanging them securely in vegetation. These small flying squirrels were identified as Hylopetes phayrei electilis (G. M. Allen, 1925) and Hylopetes alboniger (Hodgson, 1870), in video clips captured of their behavior around focal nuts. Squirrels chewed grooves encircling ellipsoid nuts or distributed on the bottoms of oblate nuts, and then used these grooves to fix nuts tightly between small twigs 0.1-0.6 cm in diameter that were connected at angles of 25-40°. The grooves carved on the nuts (concave structure) connected with Y-shaped twigs (convex structure) and thus firmly affixed the nuts to the plant in a way similar to a mortise-tenon joint used in architecture and carpentry. Cache sites were on small plants located 10-25 m away from the closest potentially nut-producing tree, a behavior that likely reduces discovery and consumption of the nuts by other animals. The adaptive squirrel behavior that shapes and fits nuts between twigs seems to be directed at providing more secure storage that increases food supply during dry periods in a humid tropical rainforest. In addition to providing such benefits for the squirrels, we suggest that this behavior also impacts the distribution of tree species in the forest.

Data availability

All data are available in the main text or the supplementary files.

Article and author information

Author details

  1. Han Xu

    Research Institute of Tropical Forestry, Chinese Academy of Forestry, Guangzhou, China
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-1085-3344
  2. Lian Xia

    College of Forestry, Hainan University, Haikou, China
    Competing interests
    The authors declare that no competing interests exist.
  3. John R Spence

    Department of Renewable Resources, University of Alberta, Edmonton, Canada
    Competing interests
    The authors declare that no competing interests exist.
  4. Mingxian Lin

    Research Institute of Tropical Forestry, Chinese Academy of Forestry, Guangzhou, China
    Competing interests
    The authors declare that no competing interests exist.
  5. Chunyang Lu

    Research Institute of Tropical Forestry, Chinese Academy of Forestry, Guangzhou, China
    Competing interests
    The authors declare that no competing interests exist.
  6. Yanpeng Li

    Research Institute of Tropical Forestry, Chinese Academy of Forestry, Guangzhou, China
    Competing interests
    The authors declare that no competing interests exist.
  7. Jie Chen

    Research Institute of Tropical Forestry, Chinese Academy of Forestry, Guangzhou, China
    Competing interests
    The authors declare that no competing interests exist.
  8. Tushou Luo

    Research Institute of Tropical Forestry, Chinese Academy of Forestry, Guangzhou, China
    Competing interests
    The authors declare that no competing interests exist.
  9. Yide Li

    Research Institute of Tropical Forestry, Chinese Academy of Forestry, Guangzhou, China
    Competing interests
    The authors declare that no competing interests exist.
  10. Suqin Fang

    State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou, China
    For correspondence
    fangsuq5@mail.sysu.edu.cn
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-1324-4640

Funding

Science and Technology Basic Work Project from Ministry of Science and Technology of the People's Republic of China (2019FY101607)

  • Han Xu

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Copyright

© 2023, Xu et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

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  1. Han Xu
  2. Lian Xia
  3. John R Spence
  4. Mingxian Lin
  5. Chunyang Lu
  6. Yanpeng Li
  7. Jie Chen
  8. Tushou Luo
  9. Yide Li
  10. Suqin Fang
(2023)
Flying squirrels use a mortise-tenon structure to fix nuts on understory twigs
eLife 12:e84967.
https://doi.org/10.7554/eLife.84967

Share this article

https://doi.org/10.7554/eLife.84967

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