A Forest of Small Signs: Following Fruits, Seeds, and Fruit Eaters

A strange thing happens when you spend enough time in forests. You start looking at it as a story rather than scenery. As someone working on seed dispersal and equally fascinated by plant taxonomy, my eyes are drawn to something different: fruit.

Fruits are clues.

Where there are fruits, fruit-eating animals (frugivores) are often nearby. By following fruits, you are unknowingly following an invisible network of plants and fruit-eating animals in a forest and over time this becomes instinctive. Whenever I enter a forest, I subconsciously look for fruit, and my mind immediately asks questions. Who eats this? Which animal can disperse this? What plant is this? Every fruit is a clue to answering these questions.

A major part of my fieldwork in Pakke Tiger Reserve, Arunachal Pradesh involves roaming in the forests to document interactions between fruits and mammals. Since rainforests contain so many different fruits, the challenge is to identify which animal consumes which fruits. Previous research provides a useful framework: brightly coloured fruits (red or orange) that stand out against a leafy background are generally consumed by birds, for whom vision is the dominant sense. Fruits that are dull coloured (yellow or brown) against a leafy background don’t stand out visually but are generally detectable by scent and are suited to mammals, many of them nocturnal, who rely primarily on olfactory cues. But some mammals don’t follow this pattern. Primates, for instance, who are generally active in the daytime, use both vision and smell. Bears are active both day and night and use both cues, often consuming bird-dispersed fruits from both trees and the ground.

Perhaps the most interesting part is learning to identify animals and understanding their interactions without seeing them. Malayan giant squirrels leave behind evidence like tiny carpenters. They take a fruit and hang upside down from branches, gripping fruits with their paws, while their sharp incisors scrape away the fruit pulp in a circular pattern. Their teeth act like a chisel, leaving behind circular pattern marks on freshly de-pulped seeds. Murid rodents (rats and mice) are another fascinating group of mammals. They sometimes cache fruits and seeds beneath leaf litter. For pod-bearing fruits like those from the Leguminosae family, murid rodents locate seeds within the pods, extract only the seeds, and leave the rest of the pod intact, with precise holes where seeds once were.

Other rodents such as the Pallas’s squirrel do not always consume whole fruits and seeds. For species like Canarium resiniferum, whose seeds are essentially nuts covered with a strong seed case, they bore holes from multiple sides of the seed case and extract the edible kernel. The Malayan giant squirrel applies a similar technique on hard-coated fruits (such as Croton persimilis and Ayenia aspera), drilling through the outer fruit coat and extracting the seeds, rather than crushing the whole fruit. When I observe this in the forest, I can only marvel at the intelligence of these creatures.

Another rodent, the porcupine, is far less subtle in the way it handles fruits and seeds. Where squirrels leave their carpenter’s signature, porcupines leave only demolished fragments. Fruit and seed become powder in their jaws.  

Animals leave lots of clues on the forest floor. Sometimes I come across pink seeds scattered beneath large trees. Touch them, and they still feel warm from being regurgitated by hornbills after swallowing fruits whole. Spotting many such seeds under a large tree often indicates a hornbill communal roosting site.

In other places, one may find a heap of seeds that retain their original colour. These are typically regurgitated by deer, barking deer, and sambar. Deer generally regurgitate around their resting spots, and one can often find their droppings and regurgitated piles in the same place. Interestingly, I once found over 500 seeds in a regurgitated pile.

Some mysteries take longer to solve. A few times, I have encountered large heaps of seeds, with a little fruit pulp on the forest floor. These piles usually contain around 30 seeds. Identifying the animal that left them was through a process of elimination. Since the seeds had no bite marks, squirrels were highly unlikely. Since the seeds were not clean, deer were ruled out. Murid rodents do cache seeds, but they do not cache in such high numbers in a tropical forest, so they were ruled out as well. That left us with frugivorous bats. Most likely, these sites were under bat roosting sites, where they collect fruits and return repeatedly to consume them, gradually building piles of discarded, uncleaned seeds below. 

Primates are wasteful feeders, following no order when feeding on fruits. They waste more than they consume, drop whole and half-eaten fruits, break fruiting branches, and litter everything below the tree. When I observe this kind of chaos below a tree, I know the culprits are most likely primates.

The more time you spend in forests, the more you notice these signs. Each sign gives you a clue about the forest — the kinds of clues that most people will walk past: a hole in a seed coat, the colour of a seed, the pattern of bite marks on seeds.

Slowly, the forest changes. It’s not just where you find different plants and animals. Forests become a web of hidden interactions you constantly experience through these clues. Every fallen seed, chewed fruit, and seed pile tells you a story about movement, animal behaviour, and cooperation between plants and animals.

The most amazing thing is that all these stories that emerge from subtle clues are never grand or cinematic. Forests reward patience. The longer you stay, the more the forest unfolds. Subtle clues give you sudden realisations and “a-ha” moments, which allow you to briefly be a part of the hidden life of the forest.

Once you begin to see forests through this lens, you will always look for the stories they tell, and never walk through them casually again.