Sea lion and seal pregnancy due date estimator
Sea Lion and Seal Pregnancy Calculator
This calculator estimates pregnancy due dates for sea lions, seals, and related pinnipeds using a selected species and a known breeding date. Many pinnipeds can include a phase called delayed implantation, where the embryo does not immediately implant and develop. This tool lets you include or exclude that phase when estimating timelines.
How the estimate is calculated
Each species uses a pregnancy duration range (minimum, typical, maximum) measured in days from breeding to birth. The core date formula is:
\[ \text{DueDate} = \text{BreedingDate} + \text{PregnancyDays} \]
Progress is calculated against the typical duration:
\[ \text{PercentComplete} = \frac{\text{DaysElapsed}}{\text{TypicalPregnancyDays}} \times 100 \]
Delayed implantation option
If Include delayed implantation is enabled and species data supports it, the calculator treats the pregnancy length as the full time from breeding to birth. If it is disabled, the calculator estimates only the active development period by subtracting the delayed implantation estimate where available.
How to use the results
The table shows three scenarios - minimum, typical, and maximum - each with an estimated due date, days remaining (based on your current date), and percent complete. If the percent complete exceeds 100%, the row is highlighted to indicate the typical due date has passed.
Practical notes
- Species differences - pregnancy timing varies across seals, sea lions, fur seals, and monk seals.
- Environment and health - nutrition, stress, and population differences can shift real birth timing.
- Use for planning - for veterinary decisions, consult qualified professionals.
FAQ
What if I do not know the exact species?
Choose the closest match. If unsure, use Other pinniped (typical) to get a general estimate.
Why is the “Current date” input included?
It changes the progress calculation (days elapsed, days remaining, and percent complete) without changing the due date itself.