Estimating Dates

How to estimate dates in ZIMS.

Many Dates can be estimated in ZIMS. Commonly estimated dates are Accession, Birth, Death and Disposition Dates. You can also estimate when animal measurements were taken.

You will commonly need to estimate dates in the following circumstances:

When entering historical information. In ZIMS, you are allowed to enter historical dates for a record that you own. If you no longer have the ownership rights of the record, you are only permitted to add data during the dates that you had ownership.
Species biology limits knowing a specific date. Examples include marsupial or denning animal birth dates.
A specific date is just not known. An example is recording a Death date for a bird carcass found in a large aviary where every bird is not accounted for daily. Another example is recording a Birth date when a few days old deer is found in the tall grass of your drive through deer exhibit.

Which estimating option you select will depend on what information you have available. As more information is found, the estimate can be edited/updated. Best Practice is to always record a Note as to why/how you estimated a Date.

Range - an undefined date between a recorded Start and an End Date

Do not record a date in the Date Field
Select Range
Enter the first possible date (Start Date) and the last possible date (End Date).
The ZIMS application will automatically fill in the date field with the mid-point between those two dates
EXAMPLE: You went on vacation on 9 May 2020 and came back on 18 May 2020. When you left there was no baby eland but when you came back there was. No one bothered to record the birth but it obviously happened sometime between those two dates. You would enter 9 May 2020 as the Start Date and 17 May 2020 as the End Date. ZIMS would calculate 13 May 2020 for the date field. You encourage your staff to record births from now on.

ApproxBefore - an undefined date before the recorded date

Enter the first possible date that it could be in the Date field
Select ApproxBefore
EXAMPLE: You are catching up on historical data entry. You have a tortoise that was never entered into ZIMS. You contact your oldest employee Mr. Runkle. He says the tortoise was there when he started work on 15 July 1950. For the Accession Date you enter 15 July 1950 and select ApproxBefore estimate as you have no idea how long before Mr. Runkle started that the tortoise arrived.

ApproxAfter - an undefined date after the recorded date

Enter the last possible date it could be in the Date field
Select ApproxAfter
EXAMPLE: You are still catching up on historical data entry and have run across a hand written medical record for a giraffe born on 5 March 1965. There is no record of when the giraffe died or was dispositioned, but the last medical entry was treatment of a foot problem on 9 June 1970. For the Disposition Date you enter 9 June 1970 and select ApproxAfter estimate as you know the giraffe was there on that date but have no further reference to go by.

ApproxVariance - a range of time with a variance of days, months or years around the recorded date

Enter a date that is midpoint in your selected variance
Select ApproxVariance
EXAMPLE: You are excited when your female red wolf finally comes out of her den with three waddling pups on 15 March 2020. You know that red wolves venture out of their dens at about 21 days. Counting back 21 days you enter 23 February 2020 in the Birth Date field. You select a Duration of 3 and a UOM as day. This means the pups could have been born from 20 February (3 days before 23 February) to 26 February (3 days after 23 February) which makes sense knowing the species biology and the normal appearance of the pups. When using Variance always double check that all days included in the Variance are possible. In our example if we selected a variance of 14 days, that would mean the pups could have been born between 9 February and 8 March making them as old a 5 weeks or as young as 2 weeks when they came out of their den and that, unless there were special circumstances such as if they were exceeding large or small when they ventured out, is not following the known species biology.

Undetermined (an undefined date possibly near the recorded date but you hope to get more information later) and Indeterminate (an undefined date possibly near the recorded date but you will never get more information later) provide little if any information and should be used as infrequently as possible.

Revised 5 March 2025