lion_reproduction: Galapagos Sea Lion Reproduction Data

In ecoteach: Educational Datasets for Ecology and Agriculture

Galapagos Sea Lion Reproduction Data

Description

This dataset contains reproductive performance data for female Galapagos sea lions (Zalophus wollebaeki) collected over a 13-year period in the Galapagos archipelago. The data includes information on mother birth dates, body mass, age at first reproduction, and offspring details. This dataset was used to study life history traits and reproductive trade-offs of this tropical apex predator in an unpredictable habitat.

Usage

lion_reproduction

Format

A data frame with 48 rows and 12 variables:

MotherID

Unique identifier for the mother sea lion

MotherBD

Mother's birth date

exact

Whether the birth date is exact ("Yes"), estimated ("No"), or unknown ("Unknown")

MotherBirthyear

Year the mother was born

AgeAtCapture

Age of the mother when first captured (in days)

AverageOneYearBodymass

Average body mass of the mother at one year of age (in kg)

PupID

Unique identifier for the pup

FirstPupBorn

Date when the first pup was born

OffspringSex

Sex of the offspring ("Male" or "Female")

SeenSince

Year the mother was first observed

SeenUntil

Year the mother was last observed

AFR

Age at first reproduction (in years)

Source

Kalberer, Stephanie, Meise, Kristine, Trillmich, Fritz, & Krüger, Oliver (2018). Reproductive performance of a tropical apex predator in an unpredictable habitat. Dryad Digital Repository. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.5061/DRYAD.6S48579")}

Examples

# Load the dataset
data(lion_reproduction)

# Basic exploration
head(lion_reproduction)
summary(lion_reproduction)

# Calculate mean age at first reproduction
mean(lion_reproduction$AFR)

# Compare age at first reproduction by offspring sex
boxplot(AFR ~ OffspringSex, data = lion_reproduction,
        main = "Age at First Reproduction by Offspring Sex",
        ylab = "Age (years)")
        
# Relationship between mother's body mass and age at first reproduction
plot(AverageOneYearBodymass ~ AFR, data = lion_reproduction,
     main = "Body Mass vs. Age at First Reproduction",
     xlab = "Age at First Reproduction (years)",
     ylab = "Average Body Mass at One Year (kg)")

ecoteach documentation built on June 29, 2025, 5:08 p.m.