Individual vocal identity is enhanced by the enlarged external nose in male proboscis monkeys (Nasalis larvatus)

Adult male proboscis monkeys, Nasalis larvatus, develop an enlarged external nose. Males often produce loud, long-distance calls filtered through the nasal passage. The enlarged nose likely functions as a visual badge of social status and a visual key representing the owner’s physical and sexual quality and thus is useful for females in selecting mates. In addition to such visual signaling, a larger external nose enhances the lower frequencies in calls, possibly exaggerating acoustic signals related to body size. Here, we used computational simulations with three-dimensional models of the nasal passage to show how the external nose modifies the acoustic property, indicating that the external nose develops to enhance lower frequencies in adults but varies in a specific formant position among adult males. This finding suggests that the external nose generates acoustic signals about physical–sexual maturity in adult males and individual identity among them. The unusual features of the soci..., , # Individual vocal identity is enhanced by the enlarged external nose in male proboscis monkeys (Nasalis larvatus)

Dataset DOI: [10.5061/dryad.5qfttdzj3](10.5061/dryad.5qfttdzj3)

## Description of the data and file structure

CT scans, STL data of 3D model, and acoustic property calculated

### Files and variables

#### **File: CTscans.zip**

**Description:** Frozen specimens of two male proboscis monkeys (adult Jaka and juvenile Niko) were thawed and scanned using a 320-row area detector CT scanner (Aquilion One™, Canon Medical Systems Corporation, Otawara, Japan) at Nihon University in Fujisawa, Japan, in 2016. The scans are in DICOM format. The scanning and reconstruction parameters are described in the header of each file.

**File: STL.zip**

**Description:** The nasal passage from the posterior and anterior naris area was extracted from each CT scans and the extracted area was transformed into a three-dimensional surface image in stereolithography (STL) format. The left and right...,